![FOSSIL ANIMAL REMAIN
In argillaceous strata, as the Lias-shale, London Clay, &c., the
fossils are frequently saturated with brilliant pyrites, or sulphuret of
iron; a mineral which decomposes upon exposure to the atmosphere,
and occasions the destruction of the specimens. The fossils of the Isle
of Sheppey are peculiarly obnoxious to this change.
The remains of vertebrated animals in the Lias,
very often occur as skeletons more or less perfect, the entire
configuration of the original being preserved in many instances (Bd. pl.
7. Petrifactions, p. 340). But the deposit in which they lie is generally
laminated, and the shale flakes off without great care; much time,
labour, and practice are therefore required, to obtain specimens of any
considerable size. To the late Miss Mary Anning, of Lyme Regis, the
merit is due, of having first accomplished this difficult task; Mr.
Hawkins has subsequently carried the art to perfection, as may be
seen in the marvellous examples of Ichthyosauri and Plesiosauri, in the
British Museum.[34]
[34] Petrifactions, Room IV. chap. iv. pp. 341, 376.
The small specimens, such as the detached paddles, groups of
vertebræ and ribs, &c., that are likely to come under the collector's
notice in his personal researches, are not difficult of preservation. Mr.
Hawkins employed a strong watery solution of gum arabic as the
cement, and plaster of Paris as the ground, using shallow wooden
trays of well-seasoned wood, in which the specimens were
permanently imbedded: the bones, scales, &c. were then varnished
with a solution of mastic, and the ground coloured bluish grey, to
imitate the Lias. I have had considerable practice in the dissection of
skeletons imbedded in Lias, and having found the method previously
described answer every purpose, have not employed that
recommended by Mr. Hawkins.
The scales of reptiles and fishes, either in connected masses or
detached, are frequently met with in great perfection, and sometimes
associated with the teeth and bones. In the Lias, even the remains of
the skin and integuments (Bd. pl. 10) have been discovered. Whenever
any part of a skeleton is found lying in shale or stone, the surrounding](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-56-320.jpg)
![STRUCTURE OF VEGETABLE
4.
—
Transverse section of a monocotyledonous stem.
Every plant is essentially an aggregation of
cells;[35] and the most simple forms of vegetation consist of a
congeries of cells (cellular tissue) of the same kind, and have no visible
fructification; such are the sea-weeds (algæ, conferæ, &c.), mosses,
and lichens. In the more complex tribes the cells become variously
modified, are elongated into tubes or vessels (vascular tissue), some of
which possess a spiral structure, and others have their sides studded
with little glands. The vascular tissue consists of two kinds of vessels.
1. The spiral vessels or tracheæ: these are membraneous tubes, with
conical extremities, having within a coil of elastic fibre spirally twisted,
and capable of being unrolled (Lign. 1, b.). 2. The ducts; which are a
modification of the structure of the spiral vessel; their extremities are
rounded or conical, and their sides marked with transverse lines, rings,
or bars. Their functions appear to be different from those of the spiral
vessels, and they are found in situations where the latter never occur.
[35] "A cell in botanical language, means a little bag composed
of membrane, and containing a living substance capable of
spontaneous growth by multiplication, or division of its parts. Of
such little bodies, millions of which may be contained within the
space of a cubic inch, all the soft parts of vegetables are composed;
in sea-weeds they are often of large size."—Dr. Harvey's Sea-side
Book, with which the reader is doubtless familiar.
The organization of the stem in the whole class of flowering plants,
possesses characters so evident, as to afford the most important aid in
the investigation of their fossil remains. Without dwelling on minor
modifications, they are separable into two divisions, namely, the
Endogenous (signifying to grow from within), and the Exogenous (to
grow from without). Both possess vascular tissue, but so differently
arranged in the two classes, as to constitute distinctive characters
which are seldom obliterated, although what was once a flexible stem,
is now a mass of flint.
Endogenous Stems.—As the seeds of the plants belonging to this
division have but one cotyledon, or seed-lobe, as the Lily, they are also](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-64-320.jpg)
![INVESTIGATION OF FOSSIL PLANT
the albumen in which the embryo lies, hence they are sometimes
named Synorhiza. The veins of the leaves (in those whose leaves are
veined), are either simple or forked; in which respect they approach
the endogens on the one hand, and the acrogens on the other.
This concise definition of the natural divisions of the vegetable
kingdom will enable the reader to comprehend the botanical principles
which must guide him in his attempt to explore the ancient floras,
whose fossil remains are generally found in a very fragmentary
condition.
I need only add that M. Ad. Brongniart, in his great work on Fossil
Plants, arranges the vegetable kingdom into five classes, viz.:—
1. Cellular Cryptogamia,[36] or Amphigens.
2. Vascular Cryptogamia,[37] or Acrogens.
3. Monocotyledons.[38]
4. Gymnospermous Dicotyledons.[39]
5. Angiospermous Dicotyledons.[40]
[36] Plants having the fructification concealed, and of cellular
structure only.
[37] Plants having the fructification concealed, and with vessels,
or vascular tissue.
[38] Flowering plants with one cotyledon; the Endogens.
[39] Plants with naked seeds; that is, destitute of a pericarp or
case.
[40] Plants with the seeds in a receptacle or pericarp, with a
style and stigma.
ON THE MODE OF INVESTIGATING FOSSIL
REMAINS OF VEGETABLES.](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-69-320.jpg)
![INVESTIGATION OF FOSSIL STEM
The distinguished authors of the British Fossil Flora justly remark,
that a few isolated, and very imperfect data, exclusively afforded by
the remains of the organs of vegetation, are but too often the sole
guide to the class, order, or genus of the fossil plants which the
geologist has to examine; hence, in most instances, a general idea
only can be obtained of the nature of the original.[41] To facilitate the
study of Fossil Botany they offer some practical suggestions, which
have served as the basis of the following directions for the
investigation of vegetable remains, and which the previous remarks
will, we trust, render intelligible.
[41] Foss. Flor. vol. I. p. xxvi.
1. The Trunk, or Stem.—Examine if the wood in a transverse
section be disposed in concentric circles (as Plate V. fig 4): if so, it
belonged to an exogenous tree: if, on the contrary, the wood appears
deposited irregularly in spots (Lign. 1, fig. 4), then the original was
endogenous. If a transverse section show remains of sinuous,
unconnected layers, resembling arcs with their ends directed outwards,
and of a solid structure, and imbedded among looser tissue, then it
belonged to an arborescent fern; see the subjoined figures (Lign. 2).
Lign. 2. Sections of Fern-Stems.
Transverse sections (half the diameter) of two stems of recent
Arborescent Ferns, to show the zone of woody fibre disposed in
arcs. This structure is seen in the silicified trunks from Chemnitz.
If the stem be in a state of preservation
that will admit of the slicing or chipping off a piece for microscopical](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-70-320.jpg)
![investigation, the process described at the conclusion of this section
should be employed.
The following data may be thus obtained. If the structure be
entirely cellular, and it can be satisfactorily ascertained that it never
possessed vascular tissue, the original belonged to the Cryptogamia;
i.e. to fuci, mosses, and the like.
If it consist of parallel tubes, and has neither pith, nor rays passing
from the centre to the circumference, the tree or plant was
endogenous, like the Palm. If any trace be present of tissue crossing
the longitudinal tubes at right angles, and radiating from the centre to
the circumference, this will prove the existence of medullary rays, and
the original must have been exogenous, as the Oak, Elm, &c.: and if in
a transverse section the tubes appear of equal size, the tree was
probably coniferous, or cycadeous (i.e. related to the plants called
Cycas and Zamia); but if larger tubes appear among the smaller ones,
disposed in a definite manner (see Plate V. fig. 4), it belonged to some
other tribe of exogenous plants.
If the walls of the tubes be studded with glands (Lign. 1, fig. 1, c;
Plate V. figs. 2b
3b
.); the fossil belongs to the Coniferæ.
If any vestige of a central pith be discovered, the exogenous nature
of the original is undoubted, for no other class, as we previously
stated, possesses a central cellular column.
The absence or presence of a true cortical investment, or bark, is
important, for a distinct bark is the characteristic of the exogenous
class:[42] a cortical integument, or rind, not separable from the
enclosed structure, indicates the monocotyledons; and the entire
absence of any rind, the cryptogamia.
[42] An apparent exception to this rule is found in the fossil
genus Clathraria, described hereafter, which has a distinct hollow
cortical cylinder, that separates from the internal axis: this is not
true bark, but is formed by the consolidation of the bases of the
petioles or leaf-stalks; see Lign. 54.](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-71-320.jpg)
![MICROSCOPICAL EXAMINATIO
mineralization. Their application is not difficult, and the student may by
their assistance obtain some general indications as to the nature of the
original trees or plants, whose petrified remains form the subject of his
examination.
ON THE MICROSCOPICAL EXAMINATION OF
FOSSIL VEGETABLES.
Mr. Nicol, who first suggested the method
now generally adopted for preparing fossil wood, coal, &c. for
microscopical examination, and which was employed by Mr. Witham in
the illustrations of his beautiful work on the structure of fossil plants,
[43] has so clearly explained the process, that by a little practice the
student will be able to prepare specimens sufficiently thin for every
useful purpose. Several lapidaries in London, (see list at the end of this
work,) polish and mount fossil vegetables and other substances, in a
very superior manner; but their charges are high, and they frequently
injure specimens by grinding them too thin, and thus obliterating
structure. I would recommend that a small chip of the specimen, if
possible in a radial direction, should be examined by reflected light,
always beginning with the lowest object-glass and eye-piece, and
ascending to the highest power; at first without any preparation;[44]
subsequently the object should be immersed in oil of turpentine, which
will render it somewhat transparent, and it then should be examined
by transmitted light. By this exploration we may detect structure, and
ascertain if the specimen be worth the trouble or expense of further
preparation.
[43] Observations on Fossil Vegetables. 4to. 1833.
[44] The drawings in Plate V. figs. 2 and 3, of fossil coniferous
wood, were from chips seen by reflected light, and without any
preparation.
Coal may be prepared for examination, by removing with a sharp
knife a thin pellicle, or a minute scraping; immerse it in a drop of oil of
turpentine on a piece of glass; then add a little Canada balsam, and
hold the glass over the flame of a lamp till the balsam is spread evenly](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-73-320.jpg)
![balsam has become solid, that part which adheres to the surface of the
glass surrounding the slice should be scraped off with the point of a
penknife; and by this operation, it will at once be seen whether the
balsam has undergone the requisite concentration; for if it flakes off
before the knife, it will be found that the slice and glass will cohere so
firmly, that in the subsequent grinding, there will be no risk of their
separating from each other; but if the balsam has not been sufficiently
concentrated, it will slide before the knife, and in that case the two
bodies will not adhere with requisite firmness. If the layer of balsam
applied to the two surfaces be not too thick, its due concentration will
be accomplished in four or five minutes, provided the application of
the heat be properly regulated. The slice must now be ground to that
degree of thinness which will permit its structure to be seen by the
help of a microscope. This will be accomplished by rubbing the slice,
by a rapid circular motion with the hand, on a piece of sheet lead,
supplied with a little emery (size No. 1.) moistened with water; when
the emery ceases to act, the muddy matter remaining should be
removed, and a fresh portion of emery applied; this must be repeated
until the surface of the slice is perfectly flat; a sheet of copper must
then be substituted for the lead, and the fossil ground as smooth as
possible by flower of emery, freed from its coarser parts. The surface
may then be polished by friction, with crocus or rotten stone, on a
transverse section of any soft wood."[45]
[45] Mr. Witham, Observations on Fossil Vegetables.](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-75-320.jpg)
![bounded by limestone rocks, they contain calc-spar, which in some
examples forms a lining of delicate crystals (Plate V. fig. 6); while in
others the kernel is transmuted into calcareous spar (see Plate III. fig.
7); but the pericarps are unchanged, and in the state of common dried
nut-shells; the water which deposited the spar in their cavities not
having left a particle of mineral matter in the ligneous substance
through which it had filtrated.
In a subterranean forest at Ferry-bridge, Yorkshire, hazel nuts in a
similar mineralized state occur, and the branches and stems of the
trees have undergone a like change; the central ligneous axis is
petrified, while the outer zones have undergone no lapidification, but
remain in the state of dry rotten wood.[46]](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-78-320.jpg)
![PEAT.—LIGNITE.—BROWN COA
JET.—WEALDEN COA
[46] Specimens are preserved in the Museum at York.
Lignite, Brown Coal, or Cannel Coal; these are terms
employed to designate certain varieties of carbonized wood, in which the
ligneous structure is more or less distinctly preserved. Lignite may be regarded
as an imperfect coal, for in its chemical properties it holds an intermediate place
between peat and bituminous coal. It is for the most part found in tertiary
formations, but is not unfrequent in ancient secondary deposits, and may occur
in the earliest sedimentary rocks which contain vegetable remains.
The newer deposits of Brown or wood-coal, are commonly situated in
depressions or basins, as if they had been produced by the submergence of
woods and forests, in a swamp or morass; and in many instances the ligneous
structure is distinct in one part of the bed, while in another the mass is a pure
black coal, differing in no respect from true coal, except that it is less dense.
Bovey Coal.—One of the most instructive deposits of brown coal in England,
is that of Bovey Heathfield, near Chudleigh in Devonshire, which is of
considerable thickness and extent, and presents all the characters of a true
coal-field; namely, beds of carbonized vegetables, alternating with layers of clay
and marl. The Bovey coal is in the state of bituminized wood, the vascular tissue
(which is coniferous in the specimens that have come under my notice) being
apparent. It is easily chipped or split, and leaves a considerable quantity of
white ashes after combustion. The layers of coal vary in thickness from one foot
to three feet; and there are eighteen or twenty in a depth of about 120 feet;
this coal-field extends seven or eight miles. No leaves or fruits have been
discovered; bitumen occurs both in the coal and in the intermediate clays.
Calcareous spar, and iron pyrites, prevail in many of the strata. In some places
this brown coal is covered by a bed of peat, in which trunks and cones of firs
are imbedded. The whole series appears to have been a lacustrine deposit;
probably formed in a lake, into whose basin rafts of pine forests were drifted by
periodical land-floods. (Org. Rem. I. p. 327).
The brown-coal formations on the banks of the Rhine, present the same
phenomena on a more extended scale, and complicated with changes induced
by volcanic action. In Iceland, where at the present time forests are unknown,
there are extensive deposits of lignite of a peculiar kind, termed surturbrand.
Jet.—The beautiful substance called Jet, is a compact lignite,
and the vascular tissue may be detected even in the most solid masses; when
prepared in very thin slices, it appears of a rich brown colour by transmitted
light, and the woody texture is visible to the naked eye. Jet is found in great
purity and abundance in the cliffs of alum-shale on the Yorkshire coast, which](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-79-320.jpg)
![were celebrated in the early centuries for the production of this substance. At
Whitby and Scarborough extensive manufactories of ornaments and trinkets of
jet are established. The sandstone cliffs near Whitby contain masses of a very
compact variety, locally termed stone-jet. In the front of the cliff, on the north-
west side of Haiburn Wyke, the stump of a tree was observed in an erect
position, about three feet high, and fifteen inches in diameter; the roots
traversed a bed of shale, and were in the state of coarse jet, but the trunk,
which extended into the sandstone, was in part silicified, while other portions
were decayed and had a sooty aspect.[47]
[47] Geological Survey of the Yorkshire Coast; by Rev. G. Young; 1828; p.
197.
Thin seams and layers, and nodular masses, as well as regular coal-fields of
lignite, occur in the tertiary formations. At Castle Hill, near Newhaven, in Sussex
(Wond. p. 239), a seam of lignite resembling the surturbrand of Iceland, a few
inches thick, is interposed between strata of red marl in which are carbonized
leaves of dicotyledonous trees.
At Alum Bay in the Isle of Wight, a layer of lignite occurs between the beds
of vertical gravel and sand of that interesting locality.
Wealden Coal.—The Wealden formation, in some districts, contains layers of
lignite, which alternate with finely laminated micaceous sandstones, marls, and
clays, abounding in minute carbonized fragments of fern-leaves, with fresh-
water shells, and entomostracous crustaceans. This series of strata so strikingly
resembles in its general aspect the characters of a coal-field, that some years
since extensive works were undertaken in Sussex, in the expectation that coal
might be obtained of suitable quality for economical purposes. The search was
unsuccessful, but the attempt deserves not the censure that was bestowed
upon it, in the infancy of geological science;[48] for experience has since shown,
that although the true coal-measures are only found beneath the Triassic and
Permian formations, good combustible bituminous coal is not necessarily
restricted to any period or series of strata, but may occur wherever the local
conditions were favourable to the accumulation and bituminization of vegetable
matter. In fact, the coal-fields of the north of Germany are of the Wealden
epoch; and this coal more closely approaches in its chemical characters the
black-coal of the ancient carboniferous formations, than any of the lignites and
brown-coals of the tertiary strata. Some of the beds are highly bituminous,
especially those of Schaumberg, and of the principality of Bückeburg, which
may rank with the best English Newcastle coal; but those layers which are
derived from coniferous trees and plants are more laminated, and somewhat
resemble the brown-coal. These deposits have originated for the most part from](https://image.slidesharecdn.com/39534-250227062223-2192f10c/85/Teaching-for-Quality-Learning-at-University-3rd-Edition-John-Biggs-80-320.jpg)
Teaching for Quality Learning at University 3rd Edition John Biggs
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- 5. TEACHING FOR QUALITY LEARNING AT UNIVERSITY Third Edition "This book is a sophisticated and insightful conceptualization of outcomes- based learning developed from the concept of constructive alignment. The first author has already made a significant contribution to the scholarship and practice of teaching and learning in universities…Together with the sec- ond author, there is now added richness through the practical implementa- tion and practices. The ideas in this book are all tried and shown to con- tribute to a more successful learning experience and outcome for students." Denise Chalmers, The Carrick Institute for Learning and Teaching in Higher Education, Australia Teaching for Quality Learning at University focuses on implementing a constructively aligned outcomes-based model at both classroom and institutional level. The theory, which is now used worldwide as a framework for good teaching and assessment, is shown to: • Assist university teachers who wish to improve the quality of their own teaching, their students' learning and their assessment of learning outcomes • Aid staff developers in providing support for teachers • Provide a framework for administrators interested in quality assurance and enhancement of teaching across the whole university The book's "how to" approach addresses several important issues: designing high level outcomes, the learning activities most likely to achieve them in small and large classes, and appropriate assessment and grading procedures. It is an accessible, jargon-free guide for all university teachers interested in enhancing their teaching and their students' learning, and for administrators and teaching developers who are involved in teaching-related decisions on an institution-wide basis. The authors have also included useful web links to further material. John Biggs is Honorary Professor of Psychology and Adjunct Professor, Centre for the Advancement of University Teaching, University of Hong Kong. Catherine Tang is Adjunct Associate Professor, Centre for the Advancement of University Teaching, University of Hong Kong, and an educational con- sultant based in Australia. Te a c h i n g f o r Q u a l i t y L e a r n i n g a t U n i v e r s i t y Biggs & Tang The Society for Research into Higher Education Teaching for Quality Learning at University Third Edition John Biggs and Catherine Tang cover design: Kate Prentice T h i r d E d i t i o n
- 6. 10:57:06:11:07 Page 1 Page 1 Teaching for Quality Learning at University
- 7. 10:57:06:11:07 Page 2 Page 2 SRHE and Open University Press Imprint Current titles include: Catherine Bargh et al.: University Leadership Ronald Barnett: Beyond all Reason Ronald Barnett and Kelly Coate: Engaging the Curriculum in Higher Education Ronald Barnett: Reshaping the University Tony Becher and Paul R. Trowler: Academic Tribes and Territories 2/e Richard Blackwell and Paul Blackmore (eds): Towards Strategic Staff Development in Higher Education David Boud and Nicky Solomon (eds): Work-based Learning Tom Bourner et al. (eds): New Directions in Professional Higher Education John Brennan and Tarla Shah: Managing Quality Higher Education Anne Brockbank and Ian McGill: Facilitating Reflective Learning in Higher Education 2/e Ann Brooks and Alison Mackinnon (eds): Gender and the Restructured University Burton R. Clark: Sustaining Change in Universities James Cornford and Neil Pollock: Putting the University Online John Cowan: On Becoming an Innovative University Teacher 2/e Vaneeta D’Andrea and David Gosling: Improving Teaching and Learning in Higher Education Sara Delamont, Paul Atkinson and Odette Parry: Supervising the Doctorate 2/e Sara Delamont and Paul Atkinson: Successful Research Careers Gerard Delanty: Challenging Knowledge Chris Duke: Managing the Learning University Heather Eggins (ed.): Globalization and Reform in Higher Education Heather Eggins and Ranald Macdonald (eds): The Scholarship of Academic Development Howard Green and Stuart Powell: Doctoral Study in Contemporary Higher Education Merle Jacob and Tomas Hellström (eds): The Future of Knowledge Production in the Academy Peter Knight: Being a Teacher in Higher Education Peter Knight and Paul Trowler: Departmental Leadership in Higher Education Peter Knight and Mantz Yorke: Assessment, Learning and Employability Ray Land: Educational Development Dina Lewis and Barbara Allan: Virtual Learning Communities David McConnell: E-Learning Groups and Communities Ian McNay (ed.): Beyond Mass Higher Education Louise Morley: Quality and Power in Higher Education Lynne Pearce: How to Examine a Thesis Moira Peelo and Terry Wareham (eds): Failing Students in Higher Education Craig Prichard: Making Managers in Universities and Colleges Stephen Rowland: The Enquiring University Teacher Maggi Savin-Baden: Problem-based Learning in Higher Education Maggi Savin-Baden: Facilitating Problem-based Learning Maggi Savin-Baden and Claire Howell Major: Foundations of Problem-based Learning Maggi Savin-Baden and Kay Wilkie: Challenging Research in Problem-based Learning David Scott et al.: Professional Doctorates Michael L. Shattock: Managing Successful Universities Maria Slowey and David Watson: Higher Education and the Lifecourse Colin Symes and John McIntyre (eds): Working Knowledge Richard Taylor, Jean Barr and Tom Steele: For a Radical Higher Education Malcolm Tight: Researching Higher Education Penny Tinkler and Carolyn Jackson: The Doctoral Examination Process Melanie Walker: Higher Education Pedagogies Melanie Walker (ed.): Reconstructing Professionalism in University Teaching Melanie Walker and Jon Nixon (eds): Reclaiming Universities from a Runaway World Diana Woodward and Karen Ross: Managing Equal Opportunities in Higher Education Mantz Yorke and Bernard Longden: Retention and Student Success in Higher Education
- 8. 10:57:06:11:07 Page 3 Page 3 Teaching for Quality Learning at University What the Student Does 3rd edition John Biggs and Catherine Tang
- 9. 10:57:06:11:07 Page 4 Page 4 Open University Press McGraw-Hill Education McGraw-Hill House Shoppenhangers Road Maidenhead Berkshire England SL6 2QL email: enquiries@openup.co.uk world wide web: www.openup.co.uk and Two Penn Plaza, New York, NY 10121–2289, USA First edition published 1999 Second edition published 2003 This third edition published 2007 Copyright © John Biggs and Catherine Tang 2007 All rights reserved. Except for the quotation of short passages for the purpose of criticism and review, no part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publisher or a licence from the Copyright Licensing Agency Limited. Details of such licences (for reprographic reproduction) may be obtained from the Copyright Licensing Agency Ltd of Saffron House, 6–10 Kirby Street, London, EC1N 8TS. A catalogue record of this book is available from the British Library ISBN-10 0 335 22126 2 (pb) 0 335 22127 0 (hb) ISBN-13: 978 0 335 22126 4 (pb) 978 0 335 22127 1 (hb) Library of Congress Cataloging-in-Publication Data CIP data has been applied for Typeset by RefineCatch Limited, Bungay, Suffolk Printed in Poland by OZ Graf. S.A. www.polskabook.pl
- 10. 10:57:06:11:07 Page 5 Page 5 Learning takes place through the active behavior of the student: it is what he does that he learns, not what the teacher does. Ralph W. Tyler (1949) If students are to learn desired outcomes in a reasonably effective man- ner, then the teacher’s fundamental task is to get students to engage in learning activities that are likely to result in their achieving those out- comes. . . . It is helpful to remember that what the student does is actu- ally more important in determining what is learned than what the teacher does. Thomas J. Shuell (1986)
- 12. 10:57:06:11:07 Page 7 Page 7 Contents List of boxes viii List of figures x List of tables xi List of tasks xiii Foreword to original edition xv Preface to third edition xvii Acknowledgements xix When you have read this book xx 1 The changing scene in university teaching 1 2 Teaching according to how students learn 15 3 Setting the stage for effective teaching 31 4 Using constructive alignment in outcomes-based teaching and learning 50 5 Designing intended learning outcomes 64 6 Contexts for effective teaching and learning 91 7 Teaching/learning activities for declarative knowledge 104 8 Teaching/learning activities for functioning knowledge 135 9 Aligning assessment with intended learning outcomes: Principles 163 10 Assessing and grading declarative knowledge 195 11 Assessing and grading functioning knowledge 217 12 Implementing constructive alignment 247 13 Constructive alignment as implemented: Some examples 284 References 318 Index 331
- 13. 10:57:06:11:07 Page 8 Page 8 List of boxes 1.1 Outcomes-based education, outcomes based education, outcome-based education and outcome based education: Which do we use? 8 4.1 How constructive alignment came into being 51 5.1 From objectives to intended learning outcomes in an engineering course 71 6.1 Adventure learning in the School of Law 95 7.1 Course preparation assignments in the teaching of sociology 113 7.2 Some examples of work-along exercises for a class in accounting of over 200 students 116 7.3 Dons struggle with stage fright 124 7.4 How reflection led to assessment being used as a TLA 130 8.1 A case in environmental education 139 8.2 An example of teaching/learning activities in acting skills 146 8.3 How not to encourage creativity 147 8.4 Designing a problem 155 9.1 Why measurement model procedures remain 176 9.2 How Faculty Office suggests final grades should be determined (and the best of British luck!) 181 9.3 The problem in Box 9.2 182 9.4 How not to ‘mark’ a dissertation 183 10.1 Two examples of students’ views on multiple-choice tests 198 10.2 What do you remember of Thomas Jefferson? 204 10.3 An ordered-outcome item for physiotherapy students 205 10.4 A chemistry ordered-outcome item 206 10.5 A warning from an ancient history essay 211 11.1 Sample items that went into an assessment portfolio in a course for teachers 223
- 14. 10:57:06:11:07 Page 9 Page 9 11.2 An example of assessing and grading a portfolio holistically 224 11.3 A powerful Venn item 236 12.1 Contents of a teaching portfolio 267 12.2 Some conditions for effective peer review (PR) of teaching for quality enhancement 270 List of boxes ix
- 15. 10:57:06:11:07 Page 10 Page 10 List of figures 1.1 Student orientation, teaching method and level of engagement 10 2.1 Desired and actual level of engagement, approaches to learning and enhancing teaching 27 4.1 Aligning intended learning outcomes, teaching and assessment tasks 59 5.1 Interrelations between two levels of graduate attributes 68 5.2 A hierarchy of verbs that may be used to form intended learning outcomes 79 7.1 Effect of rest or change of activity on learning 109 7.2 Effect of testing at end of lecture on retention 109 9.1 Learning in four topics and their formative and summative assessment 165 9.2 Teacher’s and student’s perspectives on assessment 169 12.1 Three domains of interaction in implementing constructively aligned teaching and learning 248 12.2 Theory and transformative reflective practice in teaching 250 12.3 Administrative and educational needs – striking the right balance 276
- 16. 10:57:06:11:07 Page 11 Page 11 List of tables 3.1 Aspects of teaching likely to lead to surface approaches 45 4.1 Intended learning outcomes (ILOs) for The Nature of Teaching and Learning and aligned teaching/learning activities (TLAs) 57 4.2 ILOs for The Nature of Teaching and Learning and aligned assessment tasks (ATs) 58 5.1 Some verbs for ILOs from the SOLO taxonomy 80 5.2 Some more ILO verbs from Bloom’s revised taxonomy 81 5.3 Aligning programme ILOs with graduate attributes 86 6.1 Most people learn . . . 96 6.2 Some important general criteria for any TLA: a checklist 100 7.1 What teachers and students do in a lecture leading to an ILO containing ‘explain’ 106 8.1 What teachers and students do in a lecture leading to an ILO containing ‘apply’ 137 8.2 Some areas for developing functioning knowledge with sample ILOs and the teaching/learning situations where they may be located 137 9.1 Two lexicons 180 9.2 Comparing the measurement and standards models 189 10.1 Some typical declarative and functioning knowledge verbs by SOLO level 197 10.2 Grading criteria (rubrics) for an argue-a-case assignment 210 10.3 Conversions between percentage points, letter grades and GPA 211 10.4 Example of criteria (rubrics) for grading an ILO 214 11.1 Holistic grading of a portfolio of items 225 11.2 Grading the ILO ‘reflect and improve’ 226 12.1 Demands of the measurement model and those of good teaching 277 13.1 Grading criteria for the critical review of literature in veterinary science 291
- 17. 10:57:06:11:07 Page 12 Page 12 13.2 Examples of grading criteria of different assessment tasks in accounting 296 13.3 Weighting of the three assessment tasks in engineering with respect to the ILOs 299 13.4 Some examples of grading criteria for different assessment tasks in information systems 302 13.5 A quality-enhancement measure focusing on the mean results for a given course 304 13.6 A quality-enhancement measure focusing on the results obtained by an individual student 305 13.7 Some examples of grading criteria for different assessment tasks in management sciences 309 13.8 Holistic grading for the assessment portfolio in nursing 313 xii List of tables
- 18. 10:57:06:11:07 Page 13 Page 13 List of tasks 2.1 What are your theories of teaching and learning? 16 2.2 Does your teaching encourage surface or deep approaches to learning? 28 3.1 What messages of success and failure do you convey to your students? 34 3.2 What sort of classroom climate are you creating for your students? 42 3.3 Reflection on a critical teaching/assessment incident 44 3.4 What are the major problems in your own teaching that you would like to solve? 47 5.1 SOLO levels in approaches to learning question and why 77 5.2 Writing course ILOs 84 5.3 Aligning programme ILOs with graduate attributes 86 5.4 Aligning course ILOs with programme ILOs 88 6.1 The teaching/learning context you have created 101 7.1 What happened in your large class ‘lecture’? 122 7.2 Redesigning your next large class ‘lecture’ 123 7.3 TLAs for declarative knowledge 131 8.1 Getting going with PBL 156 8.2 ILOs and TLAs in putting knowledge to work 159 9.1 Some cats to place among your collegial pigeons: six assessment dilemmas for you to consider 165 9.2 NRA or CRA? 179 9.3 Where does your assessment stand? 191 10.1 Writing ordered-outcome items 208 10.2 Design an assessment task or tasks for one of your course ILOs 215 11.1 Design portfolio assessment for functioning knowledge 227 11.2 Venn diagram of TLAs and ATs for functioning knowledge 237 11.3 Design an assessment task or tasks for one of your course ILOs 243
- 19. 10:57:06:11:07 Page 14 Page 14 12.1 Do your quality assurance processes encourage or discourage aligned teaching? 278 12.2 Follow-up of Task 3.3 279 12.3 Follow-up of Task 3.4 280 13.1 Your achievement of the intended outcomes of this book 317 xiv List of tasks
- 20. 10:57:06:11:07 Page 15 Page 15 Foreword to original edition The book is an exceptional introduction to some difficult ideas. It is full of downright good advice for every academic who wants to do something prac- tical to improve his or her students’ learning. So much of what we read on this subject is either a recycling of sensible advice topped by a thin layer of second-hand theory, or a dense treatise suitable for graduate students with a taste for the tougher courses. Not many writers are able to take the reader along the middle road, where theory applied with a delicate touch enables us to transform our practice. What is unique about Biggs is his way with words, his outspoken fluency, his precision, his depth of knowledge, his inventive- ness, or rather how he blends all these things together. Like all good teachers, he engages us from the start, and he never talks down to us. He achieves unity between his objectives, his teaching methods and his assess- ment; and thus, to adapt his own phrase, he entraps the reader in a web of consistency that optimizes his or her own learning. Perhaps not everyone will agree with Biggs’s treatment of the academic differences between phenomenography and constructivism. I’m not sure I do myself. But does it matter? The author himself takes a pragmatic approach. In the daunting task that faces lecturers in responding to the pressures of mass higher education, reduced public funding, and students who are paying more for their education, the bottom line of engineering better learning outcomes matters more than nice theoretical distinctions. Readers of the present book will especially enjoy its marvellous treatment of student assessment (particularly Chapters 3, 8 and 9).* Biggs’s most out- standing single contribution to education has been the creation of the Struc- ture of the Observed Learning Outcome (SOLO) taxonomy. Rather than read about the extraordinary practical utility of this device in secondary sources, get it from the original here. From assessing clinical decision * This material is covered in Chapters 5, 9, 10 and 11 in the present edition.
- 21. 10:57:06:11:07 Page 16 Page 16 making by medical students to classifying the outcomes of essays in history, SOLO remains the assessment apparatus of choice. There are very few writers on the subject of university teaching who can engage a reader so personally, express doubts so clearly, relate research findings so eloquently to personal experience and open our eyes to the wonder around us. John Biggs is a rare thing: an author who has the humility born of generosity and intelligence to show us how he is still learning himself. Paul Ramsden Brisbane xvi Foreword to original edition
- 22. 10:57:06:11:07 Page 17 Page 17 Preface to third edition It is very gratifying to discover that, since the second edition of this book, the concept of ‘constructive alignment’ has become part of the working theory not only of individual teachers, researchers and teaching developers, but has been implemented in many institutions and is now part of the language of quality assurance on a systemic basis. Google ‘constructive alignment’ and you now get over 24,000 references. This upsurge of interest in constructive alignment is paralleled by that in outcomes-based education (OBE): this is not surprising, given that con- structive alignment is itself one form of OBE. Unfortunately, there are other forms of OBE that have received a less than favourable press. To make sure we keep constructively aligned OBE quite separate from the others, we refer to ours as one instance of outcomes-based teaching and learning (OBTL). Our concern is exclusively with enhancing learning through quality teaching, not with managerialism, on the one hand, or with politically controversial school-based curricula, on the other. These tangled skeins are unravelled in Chapter 1. However, this edition is not intended only for those interested in outcomes-based education. The major intention is as it has always been: to enhance teaching and learning through reflective practice using construct- ive alignment as the framework for reflection. An important feature of this edition is that whereas in previous editions Catherine Tang was acknowledged as ‘a continuing source of inspiration’ to JB, she is now on board as co-author. While Catherine was head of staff development at the Hong Kong Polytechnic University (PolyU), she initiated an inter-institutional project implementing constructive alignment, funded by the University Grants Committee (UGC) of Hong Kong, resulting eventu- ally in the PolyU adopting constructive alignment throughout the univer- sity. Then both of us were invited as consultants to the institution-wide implementation of OBTL, in the form of constructive alignment, at the City University of Hong Kong. This experience has taught us a great deal, not only about implementing constructive alignment in different disciplines in
- 23. 10:58:06:11:07 Page 18 Page 18 individual classrooms, but also about the strategies – and the politics – of implementation on an institution-wide basis. The UGC is currently commit- ted to bring outcomes-based education, of which constructive alignment is one example, to all eight Hong Kong tertiary institutions in due course. The language of OBE has become widespread and for that reason, this edition uses that language consistently: for example, we now speak of ‘intended learning outcomes’ (ILOs), not ‘curriculum objectives’ as before. In fact, we are grateful for the reminder, because ‘curriculum objectives’ wasn’t quite the right term anyway, as we discuss in Chapter 5. Our recent experience has also resulted in several changes from previous editions, apart from terminology. One is that we are concerned with imple- mentation at the institutional level as well as in the classroom. What were in the previous edition special topics – large class teaching, using educational technology, teaching international students – are now dealt with as all part of designing and implementing constructively aligned teaching and assess- ment. Educational technology is now so much an integral part of university teaching that it should be treated as such, not as a special topic. And while international students undoubtedly have specials needs with regard to provi- sion for language and social support, when teaching is focused on students’ learning activities that are aligned to the intended outcomes of learning, the need to teach to presumed differences between students on the grounds of ethnicity disappears, as was made clear in the previous edition. Another change is that, following our own hands-on experience with implementing constructive alignment, this edition is even more practically oriented than the last, aimed directly at practising teachers, staff developers and administrators. Readers looking for a comprehensive update of research into student learning will not find it here. We do, however, provide two or three tasks in every chapter, making some 28 tasks in all. Doing those tasks as you, the reader, progress will without doubt enhance your understanding of constructive alignment, but you may prefer to tackle those tasks if and when you are seriously attempting to implement constructive alignment in your own teaching. In that case, the tasks are virtually a ‘how-to’ manual. To emphasize that practical orientation, and to show that implementation is possible under a variety of conditions, the final chapter gives concrete examples of implementing constructive alignment on a faculty-wide basis and of recently constructively aligned curricula in various subjects. We also provide URLs for some excellent material that is ‘up there’ waiting to be accessed. Finally, a further note on terminology. Many different terms are used to refer to degree programmes and the unit courses making up those pro- grammes. Bachelor’s degree programmes we refer to as ‘programmes’, which some refer to as ‘courses’. The units of study that make up programmes we call ‘courses’, which others refer to as ‘units’, modules’ or ‘subjects’. John Biggs, Catherine Tang Hobart, Tasmania xviii Preface to third edition
- 24. 10:58:06:11:07 Page 19 Page 19 Acknowledgements As was stated in the acknowledgements in the first and second editions, there are many ideas in this book that came about through interacting with friends and colleagues over the years. These are not repeated here. For this edition, we must mention Professor Richard Ho, for bringing us on board at the City University of Hong Kong, and Aman Shah, Tracy Lo, Roger Fung and Helen Mak, for expediting our work there. Others who have been directly helpful in providing stimulation, ideas and content for this edition are: Denise Chalmers, Catherine Chiu, Melanie Collier, Alan Dunnett, Mark Endean, Ron Kwok, David Johnston, Olivia Leung, Lawrence Li, Peter Looker, Janice McKay, Elaine Payne, Paul Ramsden, Paul Shin, Rosanne Taylor, Agnes Tiwari, Patrick Wong and Sandy Wong. Finally, we must thank Katy Hamilton, Louise Caswell, Shona Mullen and Catriona Watson of McGraw-Hill/Open University Press who have seen us through this edition, patiently and helpfully. John Biggs, Catherine Tang Hobart, Tasmania
- 25. 10:58:06:11:07 Page 20 Page 20 When you have read this book When you have read this book you should be able to: 1 Explain to a colleague what ‘constructive alignment’ is and where it fits into other models of outcomes-based education. 2 Write a set of no more than five or six intended learning outcomes, each containing a key ‘learning verb’, for a semester-long course you are teaching. 3 Reflect on your current teaching using the constructive alignment frame- work and devise: • teaching/learning activities that address your intended learning out- comes and that activate those key verbs • assessment tasks that likewise address those key verbs • rubrics or criteria for assessment that enable judgments to be made as to how well your outcomes have been addressed. 4 Develop quality enhancement processes for your own teaching. 5 Identify quality assurance and enhancement processes within your institu- tion that support the implementation of constructively aligned teaching.
- 26. 10:58:06:11:07 Page 1 Page 1 1 The changing scene in university teaching In the days when university classes contained highly selected students, the lecture and tutorial seemed to work well enough. However, the increasingly drastic changes in the tertiary sector have redrawn the uni- versity scene – not entirely disadvantageously for teaching quality. With student fees now a high proportion of funding, universities have had to improve the quality of their teaching. Many are using constructive alignment – what this book is about – as the means of doing so. We see how it may do that by looking at two very different students, Susan and Robert, who we are likely to meet in today’s classrooms. The nature of the change The university sector in most western and some eastern countries continues to change at an increasingly hectic rate. A major difference in the period separating this edition from the last, published in 2003, is that there is now an increasing recognition that teaching and learning have been neg- lected in favour of leaner and meaner universities – and that something needs to be done about it, particularly given that teaching now has a higher priority in most of today’s universities. How this came about is rather paradoxical. Twenty years ago, public funding paid for virtually 100% of costs of the tertiary sector, but today that is very far from being the case. Australia, for example, is now heading towards 30% of university funding from the public purse. The bulk of the missing funding comes from student fees. That is having profound effects on both students and on university teaching. However, the reason for the enormous cuts in public funding was not only to save money and keep taxes low, although that was the rhetoric; it was ideological. It stems from the neo-conservative belief that education is a private good and therefore one should pay for it, like one does for any other
- 27. 10:58:06:11:07 Page 2 Page 2 goods. That changed the nature of universities and the university mission: they became corporatized and competitive for markets. First, let us look at what happened to teaching and learning. Teaching and learning Now that students have to pay higher fees, they will be likely to demand high- profile programmes that are well taught and will enhance their employment prospects. Those who can, will shop around to find the right one for them. Some, using the logic that education is a commodity to be bought, feel that having paid for a degree they are entitled to be awarded one. The pressures on staff are complex: to teach in a student-friendly manner, but that may encourage them to lower standards. Such downward pressures, in some celebrated cases, have also emanated from administration, because of the funding implications of failing students. Universities in many Asian countries have improved their teaching con- siderably, so that the cost benefits of Asian students leaving their countries to complete a degree are, for Hong Kong, Singaporean, Malaysian, Korean and increasingly PRC students, not so apparent as they once were. There’ll always be linguistic and cultural reasons for moving to another country to study, but the educational case for international students to study abroad is not nearly as strong as it once was. Universities will need to provide teaching of a quality well above that which these students would receive in their home countries, not to mention making special provision for them in providing a supportive extracurricular environment and services. Despite the financial disincentives, a greater proportion of school leavers is now in higher education. Ten years ago the proportion was around 15%; now it is over 40% in many countries, and some politicians are signalling a target of up to 60%. The brightest and most committed students still go to university, as they have in the past, but they sit alongside students of rather different academic bent. The range of ability within classes is now considerable, which presents teaching-related problems to staff. Cramming students into large lecture halls is no longer good enough. Many universities, accepting that teaching is no longer the poor cousin of research, have responded positively with an increasingly teaching-friendly environment. It is increasingly being recognized that good teaching is as much a function of an institution-wide infrastructure as it is a gift with which some lucky academics are born. Many universities are funding on a larger scale than previously staff development centres and centres for teaching and learning, giving recognition of research into teaching one’s content area as legitimate research, and accepting an institution-wide responsibility for teaching-related issues, with policies and procedures that encourage good teaching and assessment. In sum, under the new financial arrangements in universities, both teaching quality and maintenance of standards are under greater pressure 2 Teaching for quality learning at university
- 28. 10:58:06:11:07 Page 3 Page 3 than ever. However, as argued in previous editions of this book, maintaining standards when the quality of students is so diverse is indeed possible. This is the ‘Robert and Susan’ problem, to which we return later in this chapter. The solution to the problem, briefly, is a matter of immersing students in a teaching environment that requires them to use learning activities that are likely to lead to the intended outcomes – and we use constructive alignment to achieve this. If a focus on improving teaching at the classroom level is one consequence of the rigorous new financial regime on universities, it had quite a different effect on the management of institutions. Managerial concerns The new agenda for universities, to sell education and to provide for market needs, makes them like any other corporation that sells a product. Vice-chancellors become CEOs of a firm; the administration, top heavy with managers, dictates policy and such matters as what courses are to be taught and what are to be cut. This has enormous implications for both research and teaching, but we concentrate only on the latter here. The managerial climate demands a new modularized credit-based curric- ulum, accountability and quality assurance. If a degree is a commodity to be sold, then the ‘customer’ will demand assurance as to the quality of the product, and that a degree commenced in one university can be com- pleted in another. As students move between university and workforce and back to university, or start their degree at one institution and finish at another, they can trade in credit transfers. Hence the appearance of bench- marking institutions, in a more formalized attempt to standardize the out- comes of education than the previous external examiner system and of the modularization of degree programmes. One version of outcomes-based education (OBE) made its appearance as a means of benchmarking and increasing accountability – but the out- comes are at institutional rather than the course level. This application and theory of OBE is quite different from that in outcomes-based teaching and learning, and constructive alignment in particular, which is concerned with more effective teaching and assessment at the course and programme level. We discuss these differences between different types of outcomes-based education later. A danger of benchmarking and the credit transfer curriculum is that one of the important characteristics of the university, the pursuit of excel- lence, is endangered. Ideally, departments should build on their strengths so that they became renowned for their research and teaching in a specific area of the discipline. Credit transfers, however, may work on the equiva- lence not only of standards but of curriculum, so the net effect is likely not to differentiate but to homogenize the offerings between universities. Care must be taken that credit transfers do not ‘dumb down’ institutions The changing scene in university teaching 3
- 29. 10:58:06:11:07 Page 4 Page 4 to the standards of the weakest. Many stakeholders are aware of this problem, claiming that market forces will force universities to continue to offer better quality, and/or different, programmes than the opposition. Universities have attempted to meet these demands relating to quality and differentiation with ‘graduate attributes’. These are outcome statements at institutional level to the effect that graduates of any of university X’s degree programmes will display certain attributes that employers would find attractive, and that hopefully might distinguish them from graduates from other universities. Such attributes would include ‘creativity’, ‘independent problem solving’, ‘professional skills’, ‘communications skills’, ‘teamwork’, ‘lifelong learning’, and so on. Graduate attributes are conceived in mainly two different ways: as generic, comprising context-free qualities of individuals, as if graduates are simply ‘creative’ whatever they do; or as embedded, that is, as abilities or ways of handling issues that are context dependent, so that creativity is only guaranteed, as it were, in a graduate’s content area. We take the embedded view here, as developed in Chapter 5. The generic view of graduate attributes often comes close to personality change. One university we know states categorically that ‘a university X graduate is culturally sensitive’ (our emphasis) – in which case, a university X graduate arrested for inciting a race riot would seem to have an excellent case for suing university X for failing to deliver. These ‘hard’, context-free claims, reifying the attribute, are hard to sustain as anything else but spin, and an inappropriate use of outcomes-based education. As Hussey and Smith (2002) put it, out- comes ‘have been misappropriated and adopted widely . . . to facilitate the managerial process’. We need to carefully distinguish between outcomes-based approaches that are used managerially and those that are used to enhance teaching and learning. An anonymous review that appeared on the Amazon UK site of the last edition of this book didn’t make that distinction. It read in part: The book (Teaching for Quality Learning at University) as a whole is an apology for the fraudulent way in which higher education is currently managed at an institutional level. Either the reviewer hadn’t read the book or the previous edition wasn’t clear enough that the very last thing this book is meant to be is an apology for managerialism (see also Biggs and Davis 2001). It is not meant to be an attack either, except in so far as managerial concerns override educational con- cerns, to the detriment of the latter – which can be a danger, as we examine in Chapter 12. So let us be absolutely clear about where we stand on outcomes-based education in the present edition. As we explain here, outcomes-based education refers to very different kinds of animal, some with bad names. 4 Teaching for quality learning at university
- 30. 10:58:06:11:07 Page 5 Page 5 What then is outcomes-based education? Since the previous edition of this book, the principles of constructive alignment have become widely used, under the more general label of ‘outcomes-based education’ (OBE) or ‘outcomes-based teaching and learn- ing’ (OBTL). Outcomes-based teaching and learning is a convenient and practical way of maintaining standards and of improving teaching. Standards are stated up front and teaching is tuned to best meet them, assessment being the means of checking how well they have been met. Outcomes-based education (OBE) has been used in quite different ways: for enhancing teaching and learning, and for furthering a managerial agenda. Outcomes-based education is sometimes identified with competency- based education. This is a mistake: competency-based education is just one example of outcomes-based education. Where it differs from other forms of OBE is in the definition of the outcomes, which in competency- based education are narrow competencies such as skills. For this reason, competency-based education is common in vocational and technical educa- tion. Constructive alignment might be called ‘competency-based’ if we restricted our intended learning outcomes to competencies and skills – but as we don’t so restrict the level of our intended learning outcomes, but extend them to as high a cognitive level a university teacher wants, constructive alignment cannot be identified with competency-based education. Yet another version of OBE has in the last decade become headline news, damned as ‘the Nazi model’ (Kjos no date), ‘left wing propaganda’ (Donnelly 2004), an ‘infection in the Australian education system’ (Brendan Nelson, one-time Australian Federal Minister of Education). The fact that the same term, outcomes-based, has been used in these different ways has created immense confusion, not to say mischief – as indeed we have seen in the case of our anonymous Amazon reviewer. Because of the confusions, and the emotion that OBE has aroused, we must clarify what we are talking about, and forthwith. OBE version one William Spady (1994) proposed an individualized programme for disad- vantaged school students that he called ‘outcome-based education’. Instead of teaching the standard disciplines, he set up targets for each student to reach so that all could achieve some sort of success. What attracted most ire was that his targets included a values component of a general humanistic kind that Christian fundamentalists thought were not the school system’s business. The Spady model, less some of the values out- comes, was picked up and adapted by several Australian state education departments. However, they made the bad mistakes, so some thought, of designing cross-disciplinary targets – no more ‘basics’, you see – and of using a sort of postmodern management-speak that many parents and The changing scene in university teaching 5
- 31. 10:58:06:11:07 Page 6 Page 6 teachers didn’t understand and that conservative politicians took for left-wing propaganda. OBE version two This version comes from the accountability movement in the USA (Ewell 1984; Miller and Ewell 2005). Here the ‘outcomes’ are at the institutional level, comprising averaged student performances and other kinds of insti- tutional outcomes, in order to meet accreditation requirements and the requests of external stakeholders like employers and policymakers. Most US institutions now have a set of outcomes statements in place, constructed with the aid of an enormous ‘template’ comprising four dimensions and 12 sub-dimensions, each containing its own outcomes (Ewell 1984): know- ledge outcomes (two sub-dimensions), skills outcomes (two sub- dimensions), attitude/value outcomes (four sub-dimensions), and relation- ships with society and with particular constituency outcomes (four sub- dimensions). The possible total of outcomes amounts to 48 in all. Unfortunately, the term ‘assessment’ in the USA can mean assessing individual students, as it does in most other English-speaking countries, but it can also mean assessing at the institutional level, as in quality assur- ance. This double meaning causes a great deal of confusion, suggesting to teachers that they should be teaching and assessing students on all or most outcome dimensions and sub-dimensions. Benchmarking exercises require teachers to stipulate how the courses they teach meet these out- come statements, using them as a template, but in our experience many teachers see each dimension and its sub-dimensions not just for bench- marking but as mandatory in their teaching and assessment of students, creating a procrustean monster to which they are to fit their own course outcome statements. As we see in Chapter 5, programme and course out- comes alike should rarely exceed five or six in number, otherwise it is prac- tically impossible to align teaching/learning activities and assessment tasks to them all. OBE version three The final version we distinguish is outcomes-based teaching and learning (OBTL), which had its seeds in the Dearing Report (1997), where outcomes are defined specifically to enhance teaching and assessment, not to serve any other purpose*. The essential features of OBTL are that, first, we state what we intend the outcomes of our teaching a particular course or programme to be. An * Hong Kong’s University Grants Committee has just adopted the very appropriate ‘Outcomes-based Approaches to Student Learning’ (OBASL) 6 Teaching for quality learning at university
- 32. 10:58:06:11:07 Page 7 Page 7 outcome statement is a statement of how we would recognize if or how well students have learned what is intended they should learn, not a prompt list of topics for teachers to ‘cover’ in a curriculum. Such an outcome statement tells us what, and how well, students are able to do something that they were unable, or only partially able, to do before teaching. Good teachers have always had some idea of that – that is one reason why they are good teachers. In outcomes-based teaching and learning, we are simply making that as explicit as we can – always allowing for unintended but desir- able outcomes. Teachers and critics often overlook this last point; that stu- dents may also learn outcomes that hadn’t been foreseen, but which are eminently desirable. Of course, we should allow for these in our assessment strategies! The issue of unexpected or unintended outcomes is discussed in Chapter 9. The second essential feature of outcomes-based teaching and learning is that teaching should be done in such a way as to increase the likelihood of most students achieving those outcomes. Talking about the topic, as in traditional teaching, is probably not the best way of doing that. We need to engage the students in learning activities that directly link to achieving the intended outcomes. The Susan and Robert story in the next section expands on this point. The third essential feature is that we need to assess how well the outcomes have been achieved. Usually this means using an assessment task that requires the student to perform the intended outcome itself. This, in many cases, is not best achieved by giving students questions to which they write answers in an invigilated exam room. Constructive alignment, the theme of this book and its previous editions, differs from other forms of outcomes-based teaching and learning in that in constructive alignment we systematically align the teaching/learning activ- ities, and the assessment tasks to the intended learning outcomes, according to the learning activities required in the outcomes. All this might sound difficult, time consuming and way too idealistic. That is not what an increasingly large number of university teachers are finding. This book will explain the background and lead you through all the stages of implementing constructive alignment, but using the outcomes-based ter- minology that is now current. In order to clarify the distinctions made in this section, and in the hope of standardizing usage that to date has been all over the place, we propose Box 1.1. Previously, there has been little consistency about hyphenation and the use of outcome- or outcomes-: both sometimes appear in the same article. So, let outcome-(singular)-based education (OBE) refer to version one, the Spady model; outcomes-(plural)-based education (OBE) refer to version two, the Ewell and like managerial models; and outcomes-based teaching and learning (OBTL) refer to version three. In this book, the form of OBTL we are using is where constructive alignment is the means of enhancing teaching and learning. The changing scene in university teaching 7
- 33. 10:58:06:11:07 Page 8 Page 8 Now let us return to the changing scene in university education and its effects on teaching and learning by looking at the ‘Robert and Susan’ problem. Making Robert learn like Susan Let us look at two students attending a lecture. Susan is academically committed; she is bright, interested in her studies and wants to do well. She has clear academic or career plans and what she learns is important to Box 1.1 Outcomes-based education, outcomes based education, outcome-based education and outcome based education: Which do we use? To hyphen or not to hyphen? Google produces identical results with or without the hyphen. Usage suggests the hyphen so let’s keep it. Outcomes-based education or outcome-based education? Outcomes-based education: 155,000 Google hits. These mostly refer to OBE at the tertiary level. Outcome-based education: 51,000 Google hits. These refer to school, primary and secondary levels, and to the tertiary level. However, William Spady first used the term outcome-based at school level, so let’s keep it at that. Solution Outcomes-based education for tertiary. Outcome-based education for school level. Problem But in that case how do we distinguish the top-down managerialist OBE, which is mainly concerned with institutional-level outcomes from our OBE, which is concerned with excellent classroom teaching? Solution Top-down managerialist OBE can stay as it is and welcome. Classroom-level OBE addresses teaching and learning: hence OBTL. Constructive alignment (22,900 Google results at time of writing) is OBTL that aligns teaching and assessment to the intended learning outcomes (see Chapter 4). 8 Teaching for quality learning at university
- 34. 10:58:06:11:07 Page 9 Page 9 her. When she learns, she goes about it in an ‘academic’ way. She comes to the lecture with sound, relevant background knowledge, possibly some ques- tions she wants answering. In the lecture, she finds an answer to a preformed question; it forms the keystone for a particular arch of knowledge she is constructing. Or it may not be the answer she is looking for and she speculates, wondering why it isn’t. In either event, she reflects on the per- sonal significance of what she is learning. Students like Susan virtually teach themselves; they typically do not need much help from us. Now take Robert. He is at university not out of a driving curiosity about a particular subject or a burning ambition to excel in a particular profession, but to obtain a qualification for a decent job. A few years ago, he would never have considered going to university. He is less committed than Susan, possibly not as bright, academically speaking. He has little background of relevant knowledge. He comes to lectures with few questions. He wants only to put in sufficient effort to pass. Robert hears the lecturer say the same words as Susan is hearing but he doesn’t see a keystone, just another brick to be recorded in his lecture notes. He believes that if he can record enough of these bricks and can remember them on cue, he’ll keep out of trouble come exam time. Students like Robert are in higher proportions in today’s classes. They do need help if they are to achieve the acceptable levels of understanding. To say that Robert is ‘unmotivated’ may be true but it is unhelpful. All it means is that he is not responding to the methods that work for Susan, the likes of whom were sufficiently visible in most classes in the good old days to satisfy us that our teaching did work. But, of course, it was the students who were doing the work and getting the results, not our teaching. The challenge we face as teachers is to teach so that Robert learns more in the manner of Susan. Figure 1.1 suggests that the present differences between Robert and Susan (point A) may be lessened by appropriate teaching (point B). Three factors are operating: • The students’ levels of engagement in relation to the level of learning activity required to achieve the intended learning outcomes in relation to a particular content and context (ranging from ‘describing’ to ‘theor- izing’, as between the dashed lines in Figure 1.1, p. 10). • The degree of learning-related activity that a teaching method is likely to stimulate. • The academic orientation of the students. Point A is towards the ‘passive’ end of the teaching method continuum, where there is a large gap between Susan’s and Robert’s levels of engage- ment. A lecture would be an example of such passive teaching and we get the picture just described. Susan is working at a high level of engagement within the target range of learning activities – relating, applying and theorizing from time to time – while Robert is taking notes and memorizing and is not within the target range of activities. If you compare this with The changing scene in university teaching 9
- 35. 10:58:06:11:07 Page 10 Page 10 Figure 2.1 (on page 27), you will see that Susan is using a ‘deep’ approach, comprising outcomes-appropriate learning activities, while Robert is operat- ing below what is required using a ‘surface’ approach. At point B, towards the ‘active’ end of the teaching method continuum, the gap between Susan and Robert is not so wide; he is actually using many of the learning activities needed to achieve the intended learning outcomes. Problem-based learning would be an example of an active teaching method, because it requires students to question, to speculate, to generate solutions, so that Robert is now using the higher order cognitive activities that Susan uses spontaneously. The teaching has narrowed the gap between their levels of active engagement in learning. This is because the teaching environment requires the students to go through learning activities that are aligned to the intended outcomes. Problem-based learning is an example of such aligned teaching: the intended outcome is that the student solve professional prob- lems and the teaching requires the student to go through solving such prob- lems. The assessment is how well the problems are solved. This is one example of constructive alignment in teaching. Of course, there are limits to what students can do that are beyond the teacher’s control – a student’s ability is one – but there are other things that are within our control and capitalizing on them is what good teaching is all Figure 1.1 Student orientation, teaching method and level of engagement 10 Teaching for quality learning at university
- 36. 10:58:06:11:07 Page 11 Page 11 about. Although Figure 1.1 is a hypothetical graph, it helps us to define good teaching, as follows: Good teaching is getting most students to use the level of cognitive processes needed to achieve the intended outcomes that the more academic students use spontaneously. Good teaching narrows the gap between the Susans and the Roberts of this world. Design of this book This book is addressed to teachers, to staff developers and to administrators. Individual teachers experience the problems, and will need to generate the solutions. Those solutions will not be found in learning a whole new bag of teaching tricks, any one of which may or may not be useful for your particular circumstances. Solutions are likely to be found in reflecting on your teaching problems, and deriving your own ways of handling them within your departmental context (see Chapters 3 and 12). But before you can do that, you need a framework with which to structure your reflections. Constructive alignment provides such a framework, anchoring teaching decisions all the time to achieving or assessing the intended learning outcomes. Staff developers, for their part, need to continue to work with indi- viduals, but not so much in generic standalone workshops, but within the context of their department. More generally, staff developers need to work with departments themselves on their teaching programmes and with administration to get the institutional policies and procedures right on teaching-related matters. If this book is to address quality teaching, we need to go beyond the individual and examine the institution. How the institution may be reflective is addressed in Chapter 12, together with the closely related theme of quality enhancement, not just quality assurance. All three – teachers, staff developers and administrators – need to immerse themselves in the ‘scholarship of teaching’ (Boyer 1990). Academics have always been teachers, but the first priority of the majority is to keep up with developments in their content discipline and to contribute to them through research. Developing teaching expertise usually takes second place: a set of priorities dictated as much by institutional structures and reward systems as by individual choice. But there is another body of knowledge, apart from their content areas, that academics also have a responsibility to address. This is the body of knowledge that underwrites good teaching, much of which is addressed in this book. In Chapter 2, we look at some of the research on student learning with a view to using that knowledge in designing more effective teaching. Students can use effective (deep) and ineffective (surface) approaches to The changing scene in university teaching 11
- 37. 10:58:06:11:07 Page 12 Page 12 their learning and, in turn, effective teaching maximizes the former and minimizes the latter. Chapter 3 sets the stage for effective teaching by look- ing at what ‘motivating’ students might mean and what the climate for teach- ing might be like: this requires that teachers reflect on what they are doing and why. The rest of the book is concerned with implementing constructive alignment in our version of outcomes-based teaching and learning, as explained in Chapter 4. Following chapters focus on crucial points in the teaching process: what constitutes a good teaching/learning environment, designing intended learning outcomes, teaching/learning activities and assessment tasks that are appropriately aligned to the outcomes and grading based on those tasks. Chapter 12 discusses questions of how best to implement constructive alignment, both by individual teachers, and by whole departments, faculties or schools, and what lessons this has for enhancing the quality of teaching and learning in the institution as a whole. Chapter 13 presents several examples of implementing constructive alignment in one whole faculty, and in several courses drawn from different content areas. Perhaps this will convince any readers, who might have lingering doubts, that constructive alignment is not pie in the sky but eminently manageable, workable and effective. Summary and conclusions The nature of the change The changing face of universities has several aspects. Financially, public funding is much decreased. The shortfall has been picked up by charging higher and higher student fees, on the neo-conservative assumption that education is a personal benefit, a commodity that should, therefore, be paid for by the individual. At the same time, proportionally more students are at university than ever before, pursuing professionally and vocationally oriented rather than the traditional academic programmes. Classrooms are thus full of a diverse range of students, all demanding the quality teaching they believe they have paid for and should be receiving. Universities are now responding to this demand for better teaching, increasingly with ‘outcomes- based education’. What is outcomes-based education? Outcomes-based education is, however, a thoroughly confused concept. This is because there are three quite different versions, with overlapping termin- ology. One version arose in a scheme for disadvantaged school students, which, for various reasons, drew criticisms from the far right of politics. 12 Teaching for quality learning at university
- 38. 10:58:06:11:07 Page 13 Page 13 Another version is used as a tool in managerialism’s new role in universities for benchmarking institutions, for accountability and credit transfers, which many academics find practically and ideologically uncomfortable. The third version we refer to as outcomes-based teaching and learning (OBTL), which is solely concerned with enhancing teaching and learning. OBTL is ideally implemented using our old friend constructive alignment, introduced in the first edition of this book in 1999. Its relevance in the present context can be seen in reference to teaching Robert and Susan. Making Robert learn like Susan Susan is the sort of ‘academic’ student teachers dream about. She hardly needs teaching: she is motivated, knowledgeable and actively learning even in lectures. Robert is unsure of his goals, is doing subjects that don’t really interest him and sits passively in class. There is a large gap between Susan’s performance and Robert’s. In a class that requires students to engage in learning activities that directly address the intended learning outcomes – where the teaching is constructively aligned, in other words – Robert is more likely to engage in the sort of learning that Susan does spontaneously. This book is designed to explain how this works and how it can be put into practice in most teaching situations. Further reading On trends in higher education Beach, C., Broadway R. and McInnes, M. (eds) (2005) Higher education in Canada. www.jdi.econ.queensu.ca/ One of the major problems in Canada is underfunding, the cost being borne by rising tuition fees. Overcrowded classes, teaching quality has declined. Students seek out good-quality academic programmes. Dearing, R. (1997) National Committee of Inquiry into Higher Education (Dearing Report). Higher Education in the Learning Society, Report of the National Committee. Norwich: HMSO. The first major thrust towards outcomes-based education in the UK. Now most universities explicitly describe course and programme outcomes in terms of the outcomes students are intended to attain, although how far these filter through into outcomes-based teaching and learning varies between institutions. Wittenberg, H. (2006) Current and Future Trends in Higher Education. Commissioned by the Austrian Federal Ministry for Education, Science and Culture. The shape of things to come in Europe: the Bologna process, involving standard- izing modular and tiered programmes across countries with credit systems ‘to make educational achievements transparent’; effects of increased participation rates, performance assessment of teaching–learning processes resulting in new forms of quality assurance. The changing scene in university teaching 13
- 39. 10:58:06:11:07 Page 14 Page 14 On Susan and Robert Buckridge, M. and Guest, R. (2007) A conversation about pedagogical responses to increased diversity in university classrooms, Higher Education Research and Development, 26, 133–146. Margaret, a staff developer, and Ross, an economics teacher, hold a dialogue about dealing with the increasingly large number of Roberts sitting alongside the Susans in our classes. Is it fair to Susan to divert resources from her in order to deal with Robert? Is it fair to Robert if you don’t? Is it really possible to obtain the optimum from each student in the same overcrowded class? Read, and draw your own conclusions. 14 Teaching for quality learning at university
- 40. 10:58:06:11:07 Page 15 Page 15 2 Teaching according to how students learn How effectively we teach depends, first, on what we think teaching is. Three levels of thinking about teaching are distinguished. The first two are ‘blame’ models, the first blaming the learner, the second the teacher. The third model integrates learning and teaching, seeing effective teaching as encouraging students to use the learning activities most likely to achieve the outcomes intended. To do this requires some knowledge of how students learn. Students may use inappropriate or low level activities, resulting in a surface approach to learning, or high- level activities appropriate to achieving the intended outcomes, result- ing in a deep approach to learning. Good teaching supports those appropriate learning activities and discourages inappropriate ones. Levels of thinking about teaching All teachers have some theory of what teaching is when they are doing it, even if they are not explicitly aware of that theory and their theories deeply affect the kind of learning environment they create in their classrooms (Gow and Kember 1993). Three common theories of teaching exist, which teachers tend to hold at different points in their teaching career. In fact, these levels describe a sequence in the development of teachers’ thinking and practice: a routemap towards reflective teaching, if you like, where the level at which a teacher operates depends on what is focused on as most important. But before discussing different theories of teaching and learning, what are yours (Task 2.1 p. 16)?
- 41. 10:58:06:11:07 Page 16 Page 16 Now let’s see what others think. Level 1. Focus: What the student is Teachers at Level 1 focus on the differences between students, as most beginning teachers do: there are good students, like Susan, and poor stu- dents, like Robert. Level 1 teachers see their responsibility as knowing the content well, and expounding it clearly. Thereafter, it’s up to the student to attend lectures, to listen carefully, to take notes, to read the recommended readings, and to make sure it’s taken on board and unloaded on cue. Susan does – good student; Robert doesn’t – poor student. At Level 1, teaching is in effect held constant – it is transmitting informa- tion, usually by lecturing – so differences in learning are due to differences between students in ability, motivation, what sort of school they went to, A level results, ethnicity and so on. Ability is usually seen as the most important factor, an interesting consequence of which is that teaching becomes not so much an educative activity as a selective one, assessment being the instrument for sorting the good students from the bad after teaching is over. Many common but counterproductive practices spring from this belief, as we dis- cuss when dealing with teaching and assessment methods. The curriculum is a list of items of content that, once expounded from the podium, have been ‘covered’. How the students receive that content and what their depth of understanding of it might be are not specifically addressed. Task 2.1 What are your theories of teaching and learning? Learning is Teaching is When you have finished this chapter, come back to these statements and see how they check out against the transmission and student learn- ing models, and the theories of teaching outlined in the chapter. Where do your own views lie? Now that you have seen these other views, have you changed your theory of teaching? Comments 16 Teaching for quality learning at university
- 42. 10:58:06:11:07 Page 17 Page 17 Level 1 is founded on a quantitative way of thinking about learning and teaching (Cole 1990), which manifests itself most obviously in assessment practices, such as ‘marking’, that is, counting up points. We examine this model, its manifestations and its consequences, in Chapter 9. The view of university teaching as transmitting information is so widely accepted that teaching and assessment the world over are based on it. Teaching rooms and media are specifically designed for one-way delivery. A teacher is the knowledgeable expert, the sage on the stage, who expounds the information the students are to absorb and to report back accurately. How well students do these things depends, in this view, on their ability, their motivation – even their ethnicity, Asian students frequently being unfairly and inaccurately stereotyped as ‘rote-learners’ (Biggs 1996). Explaining the variability in student learning on students’ characteristics is a blame-the-student theory of teaching. When students don’t learn (that is, when teaching breaks down), it is due to something the students are lacking, as exemplified in the following comments: How can I be expected to teach that lot with those A level results? They wouldn’t even have been admitted 10 years ago. They lack any motivation at all. These students lack suitable study skills. But that’s not my problem, they’ll have to go to the counselling service. In themselves, these statements may well be true: school leaving results might be poor, students nowadays may be less academically oriented. That is exactly the challenge for teachers, not their excuse for poor teaching. Blame-the-student is a comfortable theory of teaching. If students don’t learn, it’s not that there is anything wrong with the teaching, but that they are incapable, unmotivated, foreign or they possess some other non- academic defect, which is not the teacher’s responsibility to correct. Level 1 teaching is totally unreflective. It doesn’t occur to the teacher to ask the key generative question: ‘What else could I be doing?’ And until they do ask that, their teaching is unlikely to change. Level 2. Focus: What the teacher does Teachers at Level 2 focus on what teachers do. This view of teaching is still based on transmission, but transmitting concepts and understandings, not just information (Prosser and Trigwell 1998). The responsibility for ‘getting it across’ now rests to a significant extent on what the teacher does. The possibility is entertained that there may be more effective ways of teaching than what one is currently doing, which is a major advance. Learning is seen as more a function of what the teacher is doing, than of what sort of student one has to deal with. The teacher who operates at Level 2 works at obtaining an armoury of Teaching according to how students learn 17
- 43. 10:58:06:11:07 Page 18 Page 18 teaching skills. The material to be ‘got across’ includes complex under- standings, which requires much more than chalk and talk. Consider the following: I’ll settle them down with some music, then an introductory spiel: where we were last week, what we’re going to do today. Then a video clip followed by a buzz session. The questions they’re to address will be on the OH. I’ll then fire six questions at them to be answered individually. Yes, four at the back row, finger pointing, that’ll stir that lot up. Then I speak to the answers for about seven minutes, working in those two jokes I looked up. Wrap up, warning them there’s an exam question hidden in today’s session (moans of ‘Now he tells us!’ yuk, yuk). Mention what’s coming up for next week, and meantime they’re to read Chapter 10 of Bronowski. Plenty of variation in technique here, probably – almost certainly – a good student response, but the focus of this description is entirely teacher- centred. It’s about what I the teacher am doing, not on what they the students are learning. Traditional approaches to teaching development often work on what the teacher does, as do ‘how to’ courses and books that provide prescriptive advice on getting it across more effectively: • Establish clear procedural rules at the outset, such as signals for silence. • Ensure clarity: project the voice, use clear visual aids. • Eye contact with students while talking. • Don’t interrupt a large lecture with handouts: chaos is likely. This may be useful advice, but it is concerned with management, not with facilitating learning. Good management is important, but as a means of setting the stage on which good learning may occur, not as an end in itself. Level 2 is also a deficit model, the ‘blame’ this time being on the teacher. It is a view of teaching often held by university administrators, because it provides a rationale for making personnel decisions. Good teachers are those who have lots of teaching competencies. Does Dr Jones ‘have’ the appropriate competencies for tertiary level teaching? If not, he had better show evidence that he has by the time his contract comes up for renewal. However, competencies may have little to do with teaching effectiveness. A competency, such as constructing a reliable multiple-choice test, is useful only if it is appropriate to one’s teaching purposes to use a multiple-choice test. Likewise, managing educational technology, or questioning skills, or any of the other competencies tertiary teachers should ‘have’, should not be isolated from the context in which they are being used. Knowing what to do is important only if you know why, when and how you should do it. The focus should not be on the skill itself, but whether its deployment has the desired effect on student learning. Which brings us to the third level of teaching. 18 Teaching for quality learning at university
- 44. 10:58:06:11:07 Page 19 Page 19 Level 3. Focus: What the student does Teachers at Level 3 focus on what the student does and how that relates to teaching. Level 3 is a student-centred model of teaching, with teaching sup- porting learning. No longer is it possible to say: ‘I taught them, but they didn’t learn.’ Expert teaching includes mastery over a variety of teaching techniques, but unless learning takes place, they are irrelevant; the focus is on what the student does and on how well the intended outcomes are achieved. This implies a view of teaching that is not just about facts, concepts and principles to be covered and understood, but also to be clear about: 1 What it means to ‘understand’ content in the way that is stipulated in the intended learning outcomes. 2 What kind of teaching/learning activities are required to achieve those stipulated levels of understanding. The first two levels did not address these questions. The first question requires that we specify what levels of understanding we want when we teach a topic. It’s just not good enough for us to talk about it or teach with an impressive array of visual aids: the whole point, how well the students have learned, has been ignored. The second question requires the teaching/ learning activities to be specifically attuned to helping students achieve those levels of understanding. Then follow the key questions: • How do you define those levels of understanding as outcome statements? • What do students have to do to reach the level specified? • What do you have to do to find out if the outcomes have been reached at the appropriate level or not? Defining levels of understanding is basic to clarifying our intended out- comes, the subject of Chapter 5. Getting students to understand at the level required is a matter of getting them to undertake the appropriate learning activities, which is a matter dealt with in Chapters 6, 7 and 8. This is where a Level 3 student-centred theory of teaching departs from the other models of teaching. It’s not what we do but what students do that’s the important thing. Finally, we need to check that their level of under- standing displayed or their performance otherwise are what we intended. This is dealt with in Chapters 9, 10 and 11, on the theory and practice of assessment. How do students learn? Learning has been the subject of research by psychologists for the whole of last century, but remarkably little has directly resulted in improved teaching. The reason is that until recently psychologists were more concerned with developing the One Grand Theory of Learning than in studying the contexts Teaching according to how students learn 19
- 45. 10:58:06:11:07 Page 20 Page 20 in which people learned, such as schools and universities (Biggs 1993a). This focus has been rectified in the last 20 years or so, and there is now a great deal of research into the ways that students go about their learning. Appropriately, the field of study is now designated as ‘student learning’ research. Student learning research originated in Sweden, with Marton and Säljö’s (1976a, 1976b) studies of surface and deep approaches to learning. They gave students a text to read and told them they would be asked ques- tions afterwards. Students responded in two different ways. The first group learned in anticipation of the questions, concentrating anxiously on the facts and details that might be asked. They ‘skated along the surface of the text’, as Marton and Säljö put it, using a surface approach to learning. What these students remembered was a list of disjointed facts; they did not comprehend the point the author was making. The second group on the other hand set out to understand the meaning of what the author was trying to say. They went below the surface of the text to interpret that meaning, using a deep approach. They saw the big picture and how the facts and details made the author’s case. Note that the terms ‘deep’ and ‘surface’ as used here describe ways of learning a particular task, they do not describe characteristics of students. We can say that Robert might typically use a surface approach, but the whole point of this book is to set up ways of getting him to go deep. We return to this important distinction shortly. The Marton and Säljö studies struck a chord with ongoing work in other countries; in particular that of Entwistle in the United Kingdom (e.g. Entwistle and Ramsden 1983) and of Biggs in Australia (e.g. 1979, 1987a). Entwistle was working from the psychology of individual differences, Biggs from cognitive psychology, and Marton and Säljö from what they later called phenomenography. However, all had a common focus: studying learning in an institutional context. Some strong implications for teaching could be drawn from this work, as we explore in this chapter. Constructivism and phenomenography Level 3 theories of teaching are based on two main theories: phenomeno- graphy and constructivism. ‘Phenomenography’ was a term resurrected by Marton (1981) to refer to the theory that grew out of his studies with Säljö on approaches to learning and has developed since then (Marton and Booth 1997). Originally used by Sonnemann (1954) in clinical psychology, phenom- enography in the student learning context refers to the idea that the learn- er’s perspective determines what is learned, not necessarily what the teacher intends should be learned. This is another reason why our intended learning outcomes should be stated as clearly as possible and their attainment moni- tored. Teaching is a matter of changing the learner’s perspective, the way the 20 Teaching for quality learning at university
- 46. 10:58:06:11:07 Page 21 Page 21 learner sees the world and on how learners represent knowledge (Prosser and Trigwell 1998). Constructivism has a long history in cognitive psychology going back at least to Piaget (1950). Today, it takes on several forms: individual, social, cognitive, postmodern (Steffe and Gale 1995). All emphasise that the learn- ers construct knowledge with their own activities, building on what they already know. Teaching is not a matter of transmitting but of engaging stu- dents in active learning, building their knowledge in terms of what they already understand. In reflecting on our teaching and interpreting our teaching decisions, we need a theory. Whether you use phenomenography or constructivism as that theory may not matter too much, as long as your theory is consistent, under- standable and works for you. We prefer constructivism as our framework for thinking about teaching because it emphasizes what students have to do to construct knowledge, which in turn suggests the sort of learning activ- ities that teachers need to address in order to lead students to achieve the desired outcomes. In conceptualizing outcomes-based teaching and learning, constructivism works for us. Both theories agree that effective learning changes the way we see the world. The acquisition of information in itself does not bring about such a change, but the way we structure that information and think with it does. Thus, education is about conceptual change, not just the acquisition of information. Such conceptual change takes place when: 1 It is clear to both teachers and students what the intended outcomes of learning are, where all can see where they are supposed to be going. Outcomes-based teaching and learning requires this of teachers, whereas teaching in the form of ‘covering a topic’ does not. 2 Students experience the felt need to get there. The art of good teaching is to communicate that need where it is initially lacking. ‘Motivation’ is as much a product of good teaching as its prerequisite. This question is addressed in the next chapter. 3 Students feel free to focus on the task, not on watching their backs. Attempts to create a felt need to learn by the use of ill-conceived and urgent assessments are counterproductive. The game changes, becoming a matter of dealing with the test, not with engaging the task deeply. 4 Students work collaboratively and in dialogue with others, both peers and teachers. Good dialogue elicits those activities that shape, elaborate, and deepen understanding. These four points contain a wealth of implication for the design of teach- ing and for personal reflection about what one is really trying to do, as we examine in the following chapter. Teaching according to how students learn 21
- 47. 10:58:06:11:07 Page 22 Page 22 Surface and deep approaches to learning The concepts of surface and deep approaches to learning are very helpful in conceiving ways of improving teaching. Sometimes it is useful to refer to an ‘achieving’ approach (Biggs 1987a), or ‘strategic approach’ (Tait et al. 1998), referring to how ambitious and how organized students are, but we do not go into this here. Our concern is with how learning tasks are handled. The surface and deep approaches usefully describe how Robert and Susan typically go about their learning and studying – up to the point when teach- ing begins. Our aim is to teach so that Robert learns more like the way Susan does. Surface approach The surface approach arises from an intention to get the task out of the way with minimum trouble, while appearing to meet course requirements. Low cognitive-level activities are used, when higher level activities are required to do the task properly. The concept of the surface approach may be applied to any area, not only to learning. The terms ‘cutting corners’, and ‘sweep- ing under the carpet’, convey the idea: the job appears to have been done properly when it hasn’t. Applied to academic learning, examples include rote learning selected content instead of understanding it, padding an essay, listing points instead of addressing an argument, quoting secondary references as if they were primary ones; the list is endless. A common misconception is that memoriza- tion in itself indicates a surface approach (Webb 1997). However, verbatim recall is sometimes entirely appropriate, such as learning lines for a play, acquiring vocabulary or learning formulae. Memorization becomes a surface approach when understanding is required and memorizing is used to give the impression that understanding has occurred. When Robert takes notes, and selectively quotes them back, he is under-engaging in terms of what is properly required. That is a surface approach – but the problem is that it sometimes works: I hate to say it, but what you have got to do is to have a list of ‘facts’; you write down ten important points and memorize those, then you’ll do all right in the test . . . If you can give a bit of factual information – so and so did that, and concluded that – for two sides of writing, then you’ll get a good mark. (A psychology undergraduate, quoted in Ramsden 1984: 144) If the teacher of this student thought that an adequate understanding of psychology could be manifested by selectively memorizing, there would be no problem. But it is unlikely that the teacher did think that – we should hope not, anyway. This is rather a case where an inappropriate assessment 22 Teaching for quality learning at university
- 48. 10:58:06:11:07 Page 23 Page 23 task allowed the students to get a good mark on the basis of memorizing facts. As it happened, this particular student wrote essays in a highly appropriate way and later graduated with first class honours. The problem is therefore not with the student, but with the assessment task. This teacher was not being reflective while the student was highly reflective: he’d outconned the teacher. Thus, do not think that Robert is irredeemably cursed with a surface approach if he only lists unrelated bullet points as his understanding of an article. Let us say that under current conditions of teaching or assessment, he chooses to use a surface approach. Teaching and assessment methods often encourage a surface approach, because they are not aligned to the aims of teaching the subject, as in the case of the psychology teacher we just saw. The presence of a surface approach is thus a signal that something is out of kilter in our teaching or in our assessment methods. It is therefore something we can hope to address. It might in the end turn out that Robert is a student who is hopelessly addicted to surface learning, but that conclusion is way down the track yet. In using the surface approach, students focus on what Marton calls the ‘signs’ of learning; the words used, isolated facts, items treated independ- ently of each other. This prevents students from seeing what the signs signify, the meaning and structure of what is taught. Simply, they cannot see the wood for the trees. Emotionally, learning becomes a drag, a task to be got out of the way. Hence the presence of negative feelings about the learning task: anxiety, cynicism, boredom. Exhilaration or enjoyment of the task is not part of the surface approach. Factors that encourage students to adopt such an approach include: 1 From the student’s side: • An intention only to achieve a minimal pass. Such may arise from a ‘meal ticket’ view of university or from a requirement to take a subject irrelevant to the student’s programme. • Non-academic priorities exceeding academic ones. • Insufficient time; too high a workload. • Misunderstanding requirements, such as thinking that factual recall is adequate. • A cynical view of education. • High anxiety. • A genuine inability to understand particular content at a deep level. 2 From the teacher’s side: • Teaching piecemeal by bullet lists, not bringing out the intrinsic struc- ture of the topic or subject. (We hasten to add that some bullet lists, like these two here, for instance, are OK.) • Assessing for independent facts, inevitably the case when using short- answer and multiple-choice tests. • Teaching, and especially assessing, in a way that encourages cynicism: Teaching according to how students learn 23
- 49. 10:58:06:11:07 Page 24 Page 24 for example, ‘I hate teaching this section, and you’re going to hate learning it, but we’ve got to cover it.’ • Providing insufficient time to engage the tasks; emphasizing coverage at the expense of depth. • Creating undue anxiety or low expectations of success: ‘Anyone who can’t understand this isn’t fit to be at university.’ Points 1 and 2 should not be seen as entirely separate. Most of the student factors are affected by teaching. Is insufficient time to engage properly a matter of poor student planning or of poor teacher judgment? Much student cynicism is a reaction to the manner of teaching busy-work and of assess- ment. Even the last student factor, inability to understand at a deep level, refers to the task at hand and that may be a matter of poor teacher judgment concerning curriculum content as much as the student’s abilities. But there are limits. Even under the best teaching some students will still maintain a surface approach. It is probably less likely that under poor teaching students will maintain a deep approach. Even Susan. Unfortunately, it is easier to create a surface approach than it is to support a deep approach (Trigwell and Prosser 1991). The first step in improving teaching, then, is to avoid those factors that encourage a surface approach. Deep approach The deep approach arises from a felt need to engage the task appropriately and meaningfully, so the student tries to use the most appropriate cognitive activities for handling it. To Susan, who is interested in mathematics and wants to get to the bottom of the subject, cutting corners is pointless. When students feel this need-to-know, they automatically try to focus on underlying meanings, on main ideas, themes, principles, or successful appli- cations. This requires a sound foundation of relevant prior knowledge, so students needing to know will naturally try to learn the details, as well as making sure they understand the big picture. In fact, the big picture is not understandable without the details. When using the deep approach in hand- ling a task, students have positive feelings: interest, a sense of importance, challenge, exhilaration. Learning is a pleasure. Students come with ques- tions they want answered, and when the answers are unexpected, that is even better. Factors that encourage students to adopt such an approach include: 1 From the student’s side: • An intention to engage the task meaningfully and appropriately. Such an intention may arise from an intrinsic curiosity or from a determin- ation to do well. • Appropriate background knowledge. 24 Teaching for quality learning at university
- 50. 10:58:06:11:07 Page 25 Page 25 • The ability to focus at a high conceptual level, working from first prin- ciples, which in turn requires a well-structured knowledge base. • A genuine preference, and ability, for working conceptually rather than with unrelated detail. 2 From the teacher’s side: • Teaching in such a way as to explicitly bring out the structure of the topic or subject. • Teaching to elicit an active response from students, e.g. by questioning, presenting problems, rather than teaching to expound information. • Teaching by building on what students already know. • Confronting and eradicating students’ misconceptions. • Assessing for structure rather than for independent facts. • Teaching and assessing in a way that encourages a positive working atmosphere, so students can make mistakes and learn from them. • Emphasizing depth of learning, rather than breadth of coverage. • In general, and most importantly, using teaching and assessment met- hods that support the explicit aims and intended outcomes of the course. This is the constructive alignment model underlying this book. It is also known as ‘practising what you preach’. Again, the student factors (1) are not independent of teaching (2). Encouraging the need-to-know, instilling curiosity, building on students’ prior knowledge are all things that teachers can attempt to do; and, con- versely, are things that poor teaching can too easily discourage. There are many things the teacher can do to encourage deep learning. Just what will be a lot clearer by the end of this book. Desirable student learning depends both on student-based factors – abil- ity, appropriate prior knowledge, clearly accessible new knowledge – and on the teaching context, which includes teacher responsibility, informed deci- sion making and good management. But the bottom line is that teachers have to work with what material they have. Whereas lectures and tutorials might have worked in the good old days when highly selected students tended to bring their deep approaches with them, they may not work so well today. We need to create a teaching context where the Roberts of this world can go deep too. The second step in improving teaching, then, is to focus on those factors that encour- age a deep approach. What is the difference between learning approaches and learning styles? Some people speak of students’ approaches to learning as if they were learn- ing styles students use whatever the task or the teaching (Schmeck 1988); others speak of approaches as entirely determined by context, as if students Teaching according to how students learn 25
- 51. 10:58:06:11:07 Page 26 Page 26 walk into a learning situation without any preference for their way of going about learning (Marton and Säljö 1976a). We take a middle position. Students do have predilections or preferences for this or that approach, but those predilections may or may not be realized in practice, depending on the teaching context. We are dealing with an interaction between personal and contextual factors, not unlike the inter- action between heredity and environment. Both factors apply, but which predominates depends on particular situations. Have another look at Figure 1.1 (p. 10). At point A, under passive teaching, student factors make the difference, but at point B, active teaching predominates, lessening the differences between students. For an analysis of the differences between learning styles and learning approaches see Sternberg and Zhang (2001). Practically speaking, however, it is more helpful to see approaches to learn- ing as something we as teachers can hope to change, rather than as styles about which we can do little. Scores on such questionnaires as the Approaches and Study Skills Inventory for Students (ASSIST) (Tait et al. 1998) or the Study Process Questionnaire (SPQ) in either the three-factor (surface, deep and achieving) (Biggs 1987a) or two- factor versions (surface and deep only) (Biggs et al. 2001), are most usefully seen as outcomes of teaching rather than as measuring student differences. Responses to these questionnaires tell us something about the quality of the teaching environment, precisely because students’ predilections tend to adapt to the expected requirements of different teaching environments. Teaching and approaches to learning To achieve most intended learning outcomes (ILOs), a range of verbs, from high to low cognitive level, need to be activated. The highest would refer to such activities as reflecting, theorizing and so on, the lowest to memorizing, and in between are various levels of activity. When using a deep approach, students use the full range of desired learning activities; they learn termin- ology, they memorize formulae, but move from there to applying these for- mulae to new examples, and so on. When using a surface approach, there is a shortfall; students handle all tasks, low and high, with low level verbs (‘two pages of writing, etc.’). The teaching challenge is to prevent this shortfall from occurring, or to correct it where it has occurred (see Figure 2.1). The conclusion to be drawn is simple but powerful: the surface approach is to be discouraged, the deep approach encouraged – and that is the work- ing definition of good teaching used in this book. Preventing students from using a surface approach by discouraging the use of low level and inappropriate learning activities is the main thrust of the following chap- ter, while supporting the full range of appropriate learning activities, thus encouraging a deep approach, is what the remainder of the book is about. Now try Task 2.2 (p. 28) to see how your teaching has helped shape your students’ approaches to learning. 26 Teaching for quality learning at university
- 52. 10:58:06:11:07 Page 27 Page 27 Summary and conclusions Levels of thinking about teaching We distinguish three common theories of teaching, depending on what is seen as the main determinant of learning: (1) what students are, (2) what teachers do and (3) what students do. These define ‘levels’ of thinking about teaching. At Level 1, the teacher’s role is to display information, the stu- dents’ to absorb it. If students don’t have the ability or motivation to do that correctly, that is their problem. At Level 2, the teacher’s role is to explain concepts and principles, as well as to present information. For this they need Figure 2.1 Desired and actual level of engagement, approaches to learning and enhancing teaching Teaching according to how students learn 27
- 53. 10:58:06:11:07 Page 28 Page 28 various skills, techniques, and competencies. Here the focus is on what the teacher does, rather than on what the student is, and to that extent is more reflective and sophisticated. At Level 3, the focus is on what the student does: are they engaging those learning activities most likely to lead to the intended outcomes? If not, what sort of teaching/learning context would best help them? How can I know that they have achieved the intended outcomes satisfactorily? How do students learn? It is only in comparatively recent years that researchers into learning have studied learning as it takes place in institutions, by students. There is now a body of theory called ‘student learning research’ which directly relates to practice, constructivism and phenomenography being the two most influen- tial. Both emphasize that meaning is created by the learner, but constructiv- ism focuses particularly on the nature of the learning activities the student uses and on this account more readily leads to enhanced teaching. Task 2.2 Does your teaching encourage surface or deep approaches to learning? Good teaching encourages a deep approach, and discourages a surface approach, to learning. Reflect on your teaching so far, identify aspects of your teaching that have (maybe unintentionally) a encouraged a surface approach to learning: b encouraged a deep approach to learning: What future actions would you take to encourage a deep approach to learning in your students? 28 Teaching for quality learning at university
- 54. 10:58:06:11:07 Page 29 Page 29 Surface and deep approaches to learning Learning activities that are too low a level to achieve the intended learn- ing outcomes are referred to as comprising a ‘surface’ approach to learn- ing, for example memorizing to give the impression of understanding. Activities that are appropriate to achieving the outcomes are referred to as a ‘deep’ approach. At university, intended outcomes would be high level, requiring students to reflect, hypothesize, apply and so on. Surface and deep approaches to learning are not personality traits, as is sometimes thought, but are most usefully thought of as reactions to the teaching environment. Teaching and approaches to learning Good teaching supports those activities that lead to the attainment of the intended learning outcomes, as in constructive alignment. This is the topic for the most of this book. However, there is much in what the teacher does or says that can encourage inappropriate, surface approaches to learning. These are of course to be discouraged. To do so is to set the stage for effective teaching, which is the subject of the following chapter. Further reading Biggs, J.B. (1993b) From theory to practice: A cognitive systems approach, Higher Education Research and Development, 12: 73–86. Steffe, L. and Gale, J. (eds) (1995) Constructivism in Education. Hillsdale, NJ: Lawrence Erlbaum. Sternberg, R.J. and Zhang L.F. (eds) (2001) Perspectives on Thinking, Learning, and Cognitive Styles. Mahwah, NJ: Lawrence Erlbaum. The first reading applies the systems approach to student learning, the second is a fairly recent summary of the constructivist positions generally and how they apply to education. Sternberg and Zhang is a useful collection of chapters on learning/cognitive styles, approaches and orientations. Most contributors argue that styles are relevant to teaching, except Biggs, who argues that styles are a distraction and of little relevance to enhancing teaching. On applying student learning research to teaching Dart, B. and Boulton-Lewis, G. (eds) (1998) Teaching and Learning in Higher Education. Camberwell, Victoria: Australian Council for Educational Research. Prosser, M. and Trigwell, K. (1998) Teaching for Learning in Higher Education. Bucking- ham: Open University Press. Teaching according to how students learn 29
- 55. Discovering Diverse Content Through Random Scribd Documents
- 56. FOSSIL ANIMAL REMAIN In argillaceous strata, as the Lias-shale, London Clay, &c., the fossils are frequently saturated with brilliant pyrites, or sulphuret of iron; a mineral which decomposes upon exposure to the atmosphere, and occasions the destruction of the specimens. The fossils of the Isle of Sheppey are peculiarly obnoxious to this change. The remains of vertebrated animals in the Lias, very often occur as skeletons more or less perfect, the entire configuration of the original being preserved in many instances (Bd. pl. 7. Petrifactions, p. 340). But the deposit in which they lie is generally laminated, and the shale flakes off without great care; much time, labour, and practice are therefore required, to obtain specimens of any considerable size. To the late Miss Mary Anning, of Lyme Regis, the merit is due, of having first accomplished this difficult task; Mr. Hawkins has subsequently carried the art to perfection, as may be seen in the marvellous examples of Ichthyosauri and Plesiosauri, in the British Museum.[34] [34] Petrifactions, Room IV. chap. iv. pp. 341, 376. The small specimens, such as the detached paddles, groups of vertebræ and ribs, &c., that are likely to come under the collector's notice in his personal researches, are not difficult of preservation. Mr. Hawkins employed a strong watery solution of gum arabic as the cement, and plaster of Paris as the ground, using shallow wooden trays of well-seasoned wood, in which the specimens were permanently imbedded: the bones, scales, &c. were then varnished with a solution of mastic, and the ground coloured bluish grey, to imitate the Lias. I have had considerable practice in the dissection of skeletons imbedded in Lias, and having found the method previously described answer every purpose, have not employed that recommended by Mr. Hawkins. The scales of reptiles and fishes, either in connected masses or detached, are frequently met with in great perfection, and sometimes associated with the teeth and bones. In the Lias, even the remains of the skin and integuments (Bd. pl. 10) have been discovered. Whenever any part of a skeleton is found lying in shale or stone, the surrounding
- 57. block should therefore be carefully examined, to ascertain if there be traces of the skin or integuments, before any part is removed by the chisel. The specimen of an Ichthyosaurian paddle, figured in the second volume of this work, affords a good illustration of the propriety of this caution. Around the bones are seen the carbonized remains of the cartilaginous fringe that supported the integuments, and thus the perfect form of the paddle has been ascertained; had the surrounding stone been chiselled away, the most important characters would have been obliterated, as probably they have been in numerous instances. Nodular masses of indurated clay containing fishes, are often broken with difficulty in such a manner as will expose the enclosed fossil, for the nodule generally splits in various directions, and the specimen is irreparably mutilated or defaced. My friend Sir Woodbine Parish informs me that by subjecting such nodules to a high temperature—but not to a red heat—and then plunging them in cold water, they may when dry, by a properly directed blow of a hammer, be readily fractured in a direction parallel with the plane of the imbedded fossil, and the fish be laid bare in the most favourable position. The scales of fishes, and the integuments of marine reptiles, are not the only vestiges of the dermal coverings of vertebrated animals that are preserved by mineralization. Traces of the wing-integument of flying reptiles, and of the feathers of birds, are sometimes manifest: and even when every atom of the original structure has perished, the impression may remain, and afford satisfactory results. The footmarks of unknown animals are often preserved in the rocks, and the imprints of the feet of several species of bipeds, presumed to be birds of colossal size, in tracks as distinct as if but recently made, have been discovered in the New Red sandstone of North America; in the section on fossil birds, this highly interesting subject will be fully explained. The student, even from this brief review, will perceive how many valuable facts may be unnoticed, and irretrievably lost, unless attention be paid to the various circumstances under which fossil remains are presented to his notice.
- 58. Of the invertebrated orders, the most durable, and consequently the most numerous relics, are shells and corals. The integuments of the eyes, antennæ, and wings of Insects occur; and the shelly coverings of Crustaceans are not uncommon; those of the Echinoderms, the Star-fishes, and of the Crinoidea or Lily-animals, are very abundant in certain deposits. Instructions for the collection and arrangement of these fossils will be given in the chapters in which they are severally described.
- 59. PART II.
- 60. CHAPTER IV. FOSSIL BOTANY. Fossil Vegetables.—The remains of the vegetable kingdom are presented to the notice of the geologist in various conditions; in some instances these relics are but little changed in their aspect, as, for example, in the recent accumulations of mud and silt, at the bottoms of lakes and rivers, and in morasses, and peat-bogs. In tufaceous incrustations, the imprints of wood, and of leaves and stems, are often sharply defined on the solid masses of concretionary and crystalline limestone. In the ancient deposits, vegetables are found in two different states. In the one their substance is completely permeated by mineral matter; it may be calcareous (lime), siliceous (flint), ferruginous (iron), or pyritous (sulphuret of iron); and yet both the external characters, and the internal structure, may be preserved. Such are the fossil trees of the Isle of Portland, fragments of which so closely resemble decayed wood, as to deceive the casual observer, until by close examination of their texture and substance he finds that they possess the weight and hardness of stone. In the silicified wood which abounds in many of the tertiary strata, the most delicate tissues of the original are preserved, and by microscopical examination (see Pl. V.) may be displayed in a distinct and beautiful manner. In calcareous fossil wood the structure is also retained; and in many limestones, leaves and seed-vessels are well preserved. The ligneous coverings, or the husks and shells, of nuciferous fruits, and the cones or strobili of Firs and Pines, are frequently met with in an excellent state of preservation; in some rare instances indications of flowers have been observed (Lign. 67). The parts of fructification in some of the fern tribe (Lign. 25 and 27), occur in coal- shale, and in the grit of Tilgate Forest (Wond. p. 394): the pollen, and
- 61. FOSSIL VEGETABLE the resinous secretions of pines and firs, have been discovered in tertiary marls, and in the Greensand. The well-known substance. Amber, so much in request for ornaments, is unquestionably of vegetable origin; it has been found impacted in the trunks of its parent trees (Wond. p. 242). The fossil resin discovered in the London clay, at Highgate and the Isle of Sheppey, is doubtless referable to the coniferæ found in that deposit. In the Clathrariæ of Tilgate Forest, indications of a resinous secretion have been detected. The Diamond, which is pure charcoal, is probably a vegetable secretion, that has acquired a crystalline structure by electro-chemical forces. It has been converted into Coke and Graphite by the action of intense heat; and the electrical properties of the substance were changed, the Diamond being an insulator, and the Coke, a conductor of electricity. (Wond. p. 706.) When the microscope is more extensively employed in investigations of this kind, it is probable that the siliceous spines and stars which begem the foliage of many plants (as the Deutzia, Lithospermum officinale, &c), will be discovered in a fossil state, for they are as indestructible as the frustules of Diatomaceæ, and the spicules of sponges which are so common in flint and chalcedony. But vegetables occur not only as petrified stems, leaves. and fruits, associated with other remains in the strata, but also in beds of great thickness and extent, consisting wholly of plants transmuted, by that peculiar process which vegetable matter undergoes when excluded from atmospheric influence, and under great pressure, into Lignite, and Coal. And there are intermediate stages of this process, in which the form and structure of the trees and plants are apparent; and a gradual transition may be traced, from the peat-wood and submerged forests of modern epochs, in which leaves, fruits, and trunks of indigenous species are preserved, to those ancient accumulations of carbonaceous matter, whose vegetable origin the eye of science can alone detect.
- 62. For the collection and preservation of fossil vegetables, with the exception of those which are permeated with. pyrites (as those of the Isle of Sheppey, &c.), but few instructions are required. The silicified and calcareous stems are generally easy of extraction, even when imbedded in hard stone, and if broken can be repaired with glue. When the stems bear the imprints of leaf-stalks (as in Lign. 31 and 54), the surrounding stone should be carefully examined, with the view of detecting impressions, or other indications of the foliage. Delicate leaves in clay, or shale, must not be washed; a thin coat of mastic varnish, or of gum-water, applied with a camel-hair pencil, will preserve them, and render them more distinct. When a leaf, fruit, seed-vessel, or other fragile object is attached to clay or friable sandstone, it is advisable to glue the specimen to a piece of thin wood or pasteboard, of suitable proportions. The Sheppey fruits and other fossils permeated with iron pyrites, generally decompose after a few months' exposure to the air. The fruits, especially, are liable to decomposition; Mr. Bowerbank keeps his specimens in bottles of water; a solution of isinglass in spirits of wine is the best varnish to preserve such fossils, without obscuring their character and injuring their appearance: but even this method is often unavailing. The pyritified fir-cones of the Wealden decompose in like manner: I have had the misfortune to lose several unique and most instructive specimens from this cause; boiling them in linseed oil preserves them, but greatly impairs their appearance. ON THE INVESTIGATION OF THE FOSSIL REMAINS OF VEGETABLES. Vegetable Organization.—As fragments of the stems, trunks, and branches, are very often the only vestiges of fossil plants, a knowledge of the characters by which the principal divisions of the vegetable kingdom may be distinguished by their internal structure, is indispensable to the successful investigation of the Flora of the ancient world. Although I have treated of this subject in the Wonders of Geology, (Wond. p. 694,) it will here be necessary to present the
- 63. student with more ample details. The excellent introductory botanical works of Dr. Lindley, and Professor Henslow, convey full information on this, and every other department of the science, and should be consulted by those who intend to make this branch of Geology their particular study. For the general reader, and amateur collector, the following brief notice of a few obvious essential characters of vegetable organization, may perhaps afford sufficient information, to enable them to understand the principles on which the successful investigation of the nature and affinities of fossil plants must be conducted. Lign. 1. Sections of Recent Vegetables; illustrative of their internal organization. (From Dr. Lindley.) Fig. 1. — Longitudinal Section of Coniferous Wood. a. The Ducts, b. Spiral Vessels, c. Glandular vessels. 2. — Transverse section of a dicotyledonous stem. a. Pith, or central column. b. The bark. c. Medullary rays. d. Vascular tissue between the medullary rays. 3. — Elongated cellular tissue, forming the medullary rays.
- 64. STRUCTURE OF VEGETABLE 4. — Transverse section of a monocotyledonous stem. Every plant is essentially an aggregation of cells;[35] and the most simple forms of vegetation consist of a congeries of cells (cellular tissue) of the same kind, and have no visible fructification; such are the sea-weeds (algæ, conferæ, &c.), mosses, and lichens. In the more complex tribes the cells become variously modified, are elongated into tubes or vessels (vascular tissue), some of which possess a spiral structure, and others have their sides studded with little glands. The vascular tissue consists of two kinds of vessels. 1. The spiral vessels or tracheæ: these are membraneous tubes, with conical extremities, having within a coil of elastic fibre spirally twisted, and capable of being unrolled (Lign. 1, b.). 2. The ducts; which are a modification of the structure of the spiral vessel; their extremities are rounded or conical, and their sides marked with transverse lines, rings, or bars. Their functions appear to be different from those of the spiral vessels, and they are found in situations where the latter never occur. [35] "A cell in botanical language, means a little bag composed of membrane, and containing a living substance capable of spontaneous growth by multiplication, or division of its parts. Of such little bodies, millions of which may be contained within the space of a cubic inch, all the soft parts of vegetables are composed; in sea-weeds they are often of large size."—Dr. Harvey's Sea-side Book, with which the reader is doubtless familiar. The organization of the stem in the whole class of flowering plants, possesses characters so evident, as to afford the most important aid in the investigation of their fossil remains. Without dwelling on minor modifications, they are separable into two divisions, namely, the Endogenous (signifying to grow from within), and the Exogenous (to grow from without). Both possess vascular tissue, but so differently arranged in the two classes, as to constitute distinctive characters which are seldom obliterated, although what was once a flexible stem, is now a mass of flint. Endogenous Stems.—As the seeds of the plants belonging to this division have but one cotyledon, or seed-lobe, as the Lily, they are also
- 65. termed monocotyledonous; the reader therefore must remember that these terms are synonymous. These stems consist of an uniform mass of cellular tissue, in which bundles of vascular or woody fibre are imbedded; a transverse section presents a surface dotted over with spots, produced by the division of these groups of vessels, pretty uniformly distributed, but more densely arranged towards the circumference (Lign. 1, fig. 4). A slice of cane affords an illustration of this structure. The increase of these stems is effected by the formation of new cells and bundles of vessels in the central axis, which force their way among the old tissue, and occasion the condensation of the latter towards the outer edge. These plants have neither pith, concentric circles of woody fibre, nor true bark; negative characters of the highest importance in the determination of fossil stems. Exogenous Stems.—The seeds have two cotyledons, or seed-lobes, as in the Bean, hence the plants of this class are also called dicotyledonous. In these stems the cellular tissue forms a central column, or pith (Lign. 1, fig. 2, a.), and an external band, or cylinder, called the bark (fig. 2, b.); the two being connected by thin vertical plates, termed medullary rays, which are also formed of cells (fig. 2, c, c.); the diagram, Lign. 1, exhibits this arrangement. The interval between the pith and the bark, and the interspaces of the vertical radiating plates (fig. 2, d.), are filled up by woody fibre or vascular tissue, consisting of spiral and other vessels. The ligneous structure of exogenous stems consists, therefore, of a cylinder formed of wedge- shaped processes, that extend between the medullary rays to the pith, and is surrounded by the bark; a new zone of woody fibre is added annually between the bark and the former cylinder, and from this mode of increase the term exogenous is derived: a transverse section of a branch of oak or ash will show this structure. The rings, or concentric circles, are the annual zones of wood; the fine lines radiating from the centre, or pith, to the circumference, or bark, are the medullary rays (Lign. 1, fig. 2, c: see also Plate V. fig. 4). The organization above described, will be found more or less manifest in fossil wood, stems, and branches. The monocotyledonous
- 66. STRUCTURE OF CONIFER BOTANICAL PRINCIPLE structure is beautifully displayed in the silicified stems of palms from Antigua (Plate V. fig. 1, 1a .): and the dicotyledonous, in petrified trees from Egypt. The pith, medullary rays, vascular tissue, and circles of growth, are preserved in the siliceous and calcareous wood found in many parts of England. Structure of Coniferæ (cone-bearing).—The remains of a numerous family of dicotyledonous trees, termed Coniferæ, as the pine, fir, larch, &c., are so abundant in the stratified rocks, that it is necessary to describe in more detail the peculiarity of structure by which their stems and branches may be recognised. The most delicate woody tissue, as we have above stated, consists of elongated cells or tubes, of two kinds: in the one, the membrane of which they are composed is smooth: in the other, the walls of the tubes are covered by little oval or circular bodies called glands (Lign. 1, fig. 1, c.). A branch of larch or pine, split longitudinally, and viewed by a powerful lens, will exhibit the appearance here described. This glandular structure is so constantly and largely developed in the coniferæ, that although it is also possessed by other aromatic trees, we shall rarely err in referring fossil wood in which this organization is apparent, to this family of vegetables (see Plate V. figs. 2, 3). These glands in the pines and firs, are supposed to be the cells which secrete a colourless volatile oil, that exudes in the state of turpentine. From this general account of the vegetable structures that may be expected to occur in the mineral kingdom, the student will in some measure be prepared for the investigation of fossil trees and plants; but for the guidance of those who are wholly unacquainted with the principles on which the Natural System of Botany adopted in this work, is founded, I am induced to present the following concise view of the principal divisions of the vegetable kingdom, though it involves some repetition. The following summary is given nearly in Dr. Lindley's own language:— Botanical Principles.—One of the first things that strikes an inquirer into the structure of plants, is the fact, that while all species are
- 67. capable of propagating their race, the mode in which this function is effected is essentially different in different cases. In most tribes of plants, flowers are produced, and these are succeeded by fruit, containing seed, which is shed, or scattered abroad, and grows into new individuals. But in certain families (the Cryptogamia), as Ferns, Mosses, Mushrooms, and the like, neither flowers, nor seeds properly so called, have been detected; but propagation is effected by the dispersion of grains or spores, which are usually generated in the substance of the plant, and seem to have but little analogy with true seeds. Hence the vegetable kingdom is separated into two distinct groups, namely, the flowering (Phanerogamia), and the flowerless (Cryptogamia or Agamia). As the former usually possess a highly developed system of spiral and other vessels, while the latter are either altogether destitute of them, or have them only in a few of the highest orders, and those in a peculiar state, the flowering plants are termed Vasculares, and the flowerless Cellulares. And as all the flowering, or vascular plants, when they form stems, increase by an extension of their ends, and a distension or enlargement of their circumference, but the flowerless or cellular plants form their stems simply by the addition of new matter to their points, the latter are called Acrogens, signifying increase from the summit. Flowering plants are also for the most part furnished with respiratory or breathing organs (stomata), of which the flowerless vegetables are to a great extent destitute. The flowering or vascular plants are also divisible into two well marked groups, namely, the Exogens, or Dicotyledons, and the Endogens, or Monocotyledons. The Exogens (growing from without), increase by the addition of new woody matter to the outside of the stems beneath the bark; and they are further characterized by the embryo having two or more cotyledons, or seed-lobes, hence they are also called Dicotyledons; such as the Elm, Beech, &c. The Endogens, as we have previously stated, increase by the addition of ligneous matter to the inside of their stems near the
- 68. centre; and as the embryo in this class has but one cotyledon, they are likewise termed monocotyledons, as the Cane, Palm, &c. Again, exogenous plants have the young external wood connected with a central pith, by medullary processes; while endogens do not possess such a structure, having no central pith. In exogens the veins (venation) of the leaves, are disposed in meshes, like net-work, but in endogens the veins run parallel to each other. The number of parts in the flower of an exogenous plant is usually five, or its multiples: in the endogens it is commonly three, or its multiples. In the germination, the young root of exogens is a mere extension of the radicle; but in endogens it is protruded from within. Thus, in the flowering or vascular plants, we have two groups distinct from each other in their germination, the structure of their stems and leaves, their mode of growth, the arrangement of the parts of the flower, and in the structure of the embryo. The vegetable kingdom is thus separated into three natural classes, —1, the Exogens, 2, the Endogens, 3, the Acrogens; but there are likewise other divisions, a knowledge of which is of great importance in the study of fossil botany; the sub-class termed Gymnosperms especially requires notice. In the strictly exogenous and endogenous plants, the fertilizing principle is communicated to the young seeds through the medium of a stigma and style, that terminate the case or pericarp in which the seeds are enclosed: but in another important group of the vegetable kingdom, the pollen is directly applied to the ovule, without the intervention of any pericarpial apparatus; hence these are termed Gymnosperms, signifying naked seeds. These plants have the same relation to the other exogens, as frogs and analogous reptiles bear to the other orders of their Class; they comprise the two natural orders Coniferæ, and Cycadaceæ. The Gymnosperms also possess peculiarities of a subordinate nature: thus, many kinds have more than two cotyledons, and are therefore termed polycotyledons; again, the radicle usually adheres to
- 69. INVESTIGATION OF FOSSIL PLANT the albumen in which the embryo lies, hence they are sometimes named Synorhiza. The veins of the leaves (in those whose leaves are veined), are either simple or forked; in which respect they approach the endogens on the one hand, and the acrogens on the other. This concise definition of the natural divisions of the vegetable kingdom will enable the reader to comprehend the botanical principles which must guide him in his attempt to explore the ancient floras, whose fossil remains are generally found in a very fragmentary condition. I need only add that M. Ad. Brongniart, in his great work on Fossil Plants, arranges the vegetable kingdom into five classes, viz.:— 1. Cellular Cryptogamia,[36] or Amphigens. 2. Vascular Cryptogamia,[37] or Acrogens. 3. Monocotyledons.[38] 4. Gymnospermous Dicotyledons.[39] 5. Angiospermous Dicotyledons.[40] [36] Plants having the fructification concealed, and of cellular structure only. [37] Plants having the fructification concealed, and with vessels, or vascular tissue. [38] Flowering plants with one cotyledon; the Endogens. [39] Plants with naked seeds; that is, destitute of a pericarp or case. [40] Plants with the seeds in a receptacle or pericarp, with a style and stigma. ON THE MODE OF INVESTIGATING FOSSIL REMAINS OF VEGETABLES.
- 70. INVESTIGATION OF FOSSIL STEM The distinguished authors of the British Fossil Flora justly remark, that a few isolated, and very imperfect data, exclusively afforded by the remains of the organs of vegetation, are but too often the sole guide to the class, order, or genus of the fossil plants which the geologist has to examine; hence, in most instances, a general idea only can be obtained of the nature of the original.[41] To facilitate the study of Fossil Botany they offer some practical suggestions, which have served as the basis of the following directions for the investigation of vegetable remains, and which the previous remarks will, we trust, render intelligible. [41] Foss. Flor. vol. I. p. xxvi. 1. The Trunk, or Stem.—Examine if the wood in a transverse section be disposed in concentric circles (as Plate V. fig 4): if so, it belonged to an exogenous tree: if, on the contrary, the wood appears deposited irregularly in spots (Lign. 1, fig. 4), then the original was endogenous. If a transverse section show remains of sinuous, unconnected layers, resembling arcs with their ends directed outwards, and of a solid structure, and imbedded among looser tissue, then it belonged to an arborescent fern; see the subjoined figures (Lign. 2). Lign. 2. Sections of Fern-Stems. Transverse sections (half the diameter) of two stems of recent Arborescent Ferns, to show the zone of woody fibre disposed in arcs. This structure is seen in the silicified trunks from Chemnitz. If the stem be in a state of preservation that will admit of the slicing or chipping off a piece for microscopical
- 71. investigation, the process described at the conclusion of this section should be employed. The following data may be thus obtained. If the structure be entirely cellular, and it can be satisfactorily ascertained that it never possessed vascular tissue, the original belonged to the Cryptogamia; i.e. to fuci, mosses, and the like. If it consist of parallel tubes, and has neither pith, nor rays passing from the centre to the circumference, the tree or plant was endogenous, like the Palm. If any trace be present of tissue crossing the longitudinal tubes at right angles, and radiating from the centre to the circumference, this will prove the existence of medullary rays, and the original must have been exogenous, as the Oak, Elm, &c.: and if in a transverse section the tubes appear of equal size, the tree was probably coniferous, or cycadeous (i.e. related to the plants called Cycas and Zamia); but if larger tubes appear among the smaller ones, disposed in a definite manner (see Plate V. fig. 4), it belonged to some other tribe of exogenous plants. If the walls of the tubes be studded with glands (Lign. 1, fig. 1, c; Plate V. figs. 2b 3b .); the fossil belongs to the Coniferæ. If any vestige of a central pith be discovered, the exogenous nature of the original is undoubted, for no other class, as we previously stated, possesses a central cellular column. The absence or presence of a true cortical investment, or bark, is important, for a distinct bark is the characteristic of the exogenous class:[42] a cortical integument, or rind, not separable from the enclosed structure, indicates the monocotyledons; and the entire absence of any rind, the cryptogamia. [42] An apparent exception to this rule is found in the fossil genus Clathraria, described hereafter, which has a distinct hollow cortical cylinder, that separates from the internal axis: this is not true bark, but is formed by the consolidation of the bases of the petioles or leaf-stalks; see Lign. 54.
- 72. The markings on the stems, occasioned by the scars or cicatrices left by the separation of the petioles or leaf-stalks (as on the stalk of a cabbage), afford important evidence, since they are commonly present, even when the cylindrical trunk is compressed into a flat thin layer of coal; as we shall often have occasion to remark. In this place it need only be stated, that by these scars may be detected the position of the leaves, and the form of the bases of the petioles or leaf-stalks; their probable direction, whether they were opposite, alternate, verticillate or spirally disposed, deciduous or persistent, imbricated or remote. Even when no traces of the leaves remain, the origin of the branches, and their bifurcation, may perhaps be determinable. 2. The Leaves.—In a fossil state the texture and surface of the leaves are sometimes preserved; but in general the outline of the leaf, its division and arrangement, and its mode of venation, can alone be ascertained. The venation, that is, the form and distribution of the vascular tissue, or vessels, through the leaf, is the most important character for our guidance; and Dr. Lindley offers the following suggestions on this point. If the veins be all parallel, not branched, or only connected by little transverse bars, and the leaves undivided (as in the Lily or Hyacinth), the plant was probably endogenous; but if the leaf be divided or pinnated, it may be referable to Cycadeæ (Lign. 45). Leaves having the veins of equal, or nearly equal thickness, and dichotomous (forked), or very fine, and simply divided, belong to the fern tribe; to this division an immense proportion of the foliage found in the carboniferous strata is referable; the genera of fossil ferns have been constructed principally from the venation. If the veins of a leaf be obviously of unequal thickness, and reticulated, or disposed in net-like meshes, as in the rose and apple, the original was dicotyledonous (Plate III, figs. 4, 8). Leaves of a large size, destitute of veins, and irregularly divided, probably belong to fuci, or other marine plants (Lign. 10). Such are the rules for the investigation and interpretation of the characters of stems and foliage, which have been preserved by
- 73. MICROSCOPICAL EXAMINATIO mineralization. Their application is not difficult, and the student may by their assistance obtain some general indications as to the nature of the original trees or plants, whose petrified remains form the subject of his examination. ON THE MICROSCOPICAL EXAMINATION OF FOSSIL VEGETABLES. Mr. Nicol, who first suggested the method now generally adopted for preparing fossil wood, coal, &c. for microscopical examination, and which was employed by Mr. Witham in the illustrations of his beautiful work on the structure of fossil plants, [43] has so clearly explained the process, that by a little practice the student will be able to prepare specimens sufficiently thin for every useful purpose. Several lapidaries in London, (see list at the end of this work,) polish and mount fossil vegetables and other substances, in a very superior manner; but their charges are high, and they frequently injure specimens by grinding them too thin, and thus obliterating structure. I would recommend that a small chip of the specimen, if possible in a radial direction, should be examined by reflected light, always beginning with the lowest object-glass and eye-piece, and ascending to the highest power; at first without any preparation;[44] subsequently the object should be immersed in oil of turpentine, which will render it somewhat transparent, and it then should be examined by transmitted light. By this exploration we may detect structure, and ascertain if the specimen be worth the trouble or expense of further preparation. [43] Observations on Fossil Vegetables. 4to. 1833. [44] The drawings in Plate V. figs. 2 and 3, of fossil coniferous wood, were from chips seen by reflected light, and without any preparation. Coal may be prepared for examination, by removing with a sharp knife a thin pellicle, or a minute scraping; immerse it in a drop of oil of turpentine on a piece of glass; then add a little Canada balsam, and hold the glass over the flame of a lamp till the balsam is spread evenly
- 74. over the specimen. But without any preparation, the surface of coal recently broken may be successfully investigated. One of the most interesting examples of coniferous structure in coal that my cabinet contains, was discovered by my son in a piece lying on the fire, which had been cracked by the heat; and I have another fragment, showing the spiral vessels, and coniferous glands, which the Rev. J. B. Reade obtained under similar circumstances. But for choice specimens, the following method is to be employed; and in many cases no other plan will succeed. Sections of teeth, bone, marble, &c. may be prepared by a like process. MODE OF PREPARING SLICES OF FOSSIL WOOD FOR MICROSCOPICAL EXAMINATION. "Let a thin slice be cut off from the fossil wood, in a direction perpendicular to the length of its fibres—the slice thus obtained must be ground perfectly flat, and polished. The polished surface is then to be cemented to a piece of plate glass (3 in. long and 1 in. wide) by Canada balsam—a thin layer of balsam must be applied to the polished surface of the slice, and also to one side of the glass—the slice and the glass are now to be laid on any thin plate of metal, and gradually heated over a slow fire, or a spirit lamp, to concentrate the balsam. The heat must not be so great as to throw the balsam into a state of ebullition; for if air bubbles be formed, it is difficult to get rid of them, and if not removed they will prevent the complete adhesion of the two surfaces when applied to each other; the heat of the metal should never be so great that the fingers may not be held in contact with it for a few seconds without inconvenience. When air bubbles are formed, they should be displaced by a small piece of wood tapering to a point; when the balsam is thought to be sufficiently concentrated, and all the air bubbles have disappeared, the slice and glass may be taken from the heated metal, and pressed closely together; a slight degree of pressure will suffice to expel the super-abundant balsam, and this will be facilitated by gently sliding the specimen to and fro on the glass; by this kind of motion any air that may have got entangled when the two surfaces were brought in contact, will also be removed. When the whole is cooled down to the temperature of the air, and the
- 75. balsam has become solid, that part which adheres to the surface of the glass surrounding the slice should be scraped off with the point of a penknife; and by this operation, it will at once be seen whether the balsam has undergone the requisite concentration; for if it flakes off before the knife, it will be found that the slice and glass will cohere so firmly, that in the subsequent grinding, there will be no risk of their separating from each other; but if the balsam has not been sufficiently concentrated, it will slide before the knife, and in that case the two bodies will not adhere with requisite firmness. If the layer of balsam applied to the two surfaces be not too thick, its due concentration will be accomplished in four or five minutes, provided the application of the heat be properly regulated. The slice must now be ground to that degree of thinness which will permit its structure to be seen by the help of a microscope. This will be accomplished by rubbing the slice, by a rapid circular motion with the hand, on a piece of sheet lead, supplied with a little emery (size No. 1.) moistened with water; when the emery ceases to act, the muddy matter remaining should be removed, and a fresh portion of emery applied; this must be repeated until the surface of the slice is perfectly flat; a sheet of copper must then be substituted for the lead, and the fossil ground as smooth as possible by flower of emery, freed from its coarser parts. The surface may then be polished by friction, with crocus or rotten stone, on a transverse section of any soft wood."[45] [45] Mr. Witham, Observations on Fossil Vegetables.
- 76. PEAT-WOOD, LIGNITE, AND COA CHAPTER V. ON PEAT-WOOD, LIGNITE, AND COAL. Lign. 3. Nodule of Ironstone inclosing a Fern-leaf. Coalbrook Dale. Fig. 1.—The nodule in its natural state. 2, 3. — The same, split open longitudinally. The leaf remains attached to fig. 2, and the impression of its upper surface is seen on fig. 3. 4.—Outline of the form of the leaf, which is a species of Pecopteris. Before entering upon the examination of the specific and generic characters of fossil plants, and the natural relations of the extinct forms with those of the existing Floras, it will be requisite to notice those vast beds of vegetable matter, in various states of carbonization, which occur in the palæozoic, secondary, and tertiary formations. Submerged Forests. Peat.—The phenomenon of extensive tracts of marsh-land, with layers of prostrate trees of all ages, lying but a few feet beneath the common alluvial soil, is of frequent occurrence, both inland, and in many places along the shores of our island. (Geol. S. E.
- 77. p. 18). These submerged forests are generally situated below the level of the sea, and afford unquestionable proof of subsidences of the land. The trees are of the kinds indigenous to the districts in which they occur; and leaves and seeds of the hazel, beech, elm, &c. are often preserved in the silt in which the prostrate forests are imbedded. On the Sussex coast there are accumulations of this kind, at Bexhill, Pevensey levels, Felpham, &c. The extensive subterranean forests exposed in the Fens of Lincolnshire by the operations carried on for draining that district, must be familiar to those who travel by the Great Northern Railway: the protruding upright stems, broken off at a short distance above the primitive soil, will remind the geological observer of the petrified forest of the Isle of Portland. The wood in these cases has undergone no change but that of being dyed black, by an impregnation of solutions of iron; and many trunks are in so sound a state as to be employed in building. The oak timbers of the Royal George, lately raised up from off Portsmouth, after being immersed in silt about sixty years, closely resemble in colour and texture the wood of the submerged forests. Skeletons of deer, horse, swine, &c. are occasionally found imbedded in these subterranean accumulations of vegetable remains; and sometimes canoes, formed of the trunk of an oak, constructed by the aboriginal inhabitants of Britain, with stone implements called celts, are met with at considerable depths. In the peat-bogs of Ireland (Wond. p. 66), large forest trees often occur, together with the skeletons of the elk, deer, and other animals of the chase; and in a few instances the bodies of the primitive hunters, wrapped in skins, have been discovered. In Belfast Lough, a bed of peat is situated beneath the ordinary level of the waters, but is generally left bare at the ebb tides. Trunks and branches of trees, with vast quantities of hazel nuts, are imbedded in the peat; the whole being covered by layers of sand, and blue clay, or silt. In most cases the pericarps of the nuts are empty, the kernels having perished; but on the eastern side of the Lough, which is
- 78. bounded by limestone rocks, they contain calc-spar, which in some examples forms a lining of delicate crystals (Plate V. fig. 6); while in others the kernel is transmuted into calcareous spar (see Plate III. fig. 7); but the pericarps are unchanged, and in the state of common dried nut-shells; the water which deposited the spar in their cavities not having left a particle of mineral matter in the ligneous substance through which it had filtrated. In a subterranean forest at Ferry-bridge, Yorkshire, hazel nuts in a similar mineralized state occur, and the branches and stems of the trees have undergone a like change; the central ligneous axis is petrified, while the outer zones have undergone no lapidification, but remain in the state of dry rotten wood.[46]
- 79. PEAT.—LIGNITE.—BROWN COA JET.—WEALDEN COA [46] Specimens are preserved in the Museum at York. Lignite, Brown Coal, or Cannel Coal; these are terms employed to designate certain varieties of carbonized wood, in which the ligneous structure is more or less distinctly preserved. Lignite may be regarded as an imperfect coal, for in its chemical properties it holds an intermediate place between peat and bituminous coal. It is for the most part found in tertiary formations, but is not unfrequent in ancient secondary deposits, and may occur in the earliest sedimentary rocks which contain vegetable remains. The newer deposits of Brown or wood-coal, are commonly situated in depressions or basins, as if they had been produced by the submergence of woods and forests, in a swamp or morass; and in many instances the ligneous structure is distinct in one part of the bed, while in another the mass is a pure black coal, differing in no respect from true coal, except that it is less dense. Bovey Coal.—One of the most instructive deposits of brown coal in England, is that of Bovey Heathfield, near Chudleigh in Devonshire, which is of considerable thickness and extent, and presents all the characters of a true coal-field; namely, beds of carbonized vegetables, alternating with layers of clay and marl. The Bovey coal is in the state of bituminized wood, the vascular tissue (which is coniferous in the specimens that have come under my notice) being apparent. It is easily chipped or split, and leaves a considerable quantity of white ashes after combustion. The layers of coal vary in thickness from one foot to three feet; and there are eighteen or twenty in a depth of about 120 feet; this coal-field extends seven or eight miles. No leaves or fruits have been discovered; bitumen occurs both in the coal and in the intermediate clays. Calcareous spar, and iron pyrites, prevail in many of the strata. In some places this brown coal is covered by a bed of peat, in which trunks and cones of firs are imbedded. The whole series appears to have been a lacustrine deposit; probably formed in a lake, into whose basin rafts of pine forests were drifted by periodical land-floods. (Org. Rem. I. p. 327). The brown-coal formations on the banks of the Rhine, present the same phenomena on a more extended scale, and complicated with changes induced by volcanic action. In Iceland, where at the present time forests are unknown, there are extensive deposits of lignite of a peculiar kind, termed surturbrand. Jet.—The beautiful substance called Jet, is a compact lignite, and the vascular tissue may be detected even in the most solid masses; when prepared in very thin slices, it appears of a rich brown colour by transmitted light, and the woody texture is visible to the naked eye. Jet is found in great purity and abundance in the cliffs of alum-shale on the Yorkshire coast, which
- 80. were celebrated in the early centuries for the production of this substance. At Whitby and Scarborough extensive manufactories of ornaments and trinkets of jet are established. The sandstone cliffs near Whitby contain masses of a very compact variety, locally termed stone-jet. In the front of the cliff, on the north- west side of Haiburn Wyke, the stump of a tree was observed in an erect position, about three feet high, and fifteen inches in diameter; the roots traversed a bed of shale, and were in the state of coarse jet, but the trunk, which extended into the sandstone, was in part silicified, while other portions were decayed and had a sooty aspect.[47] [47] Geological Survey of the Yorkshire Coast; by Rev. G. Young; 1828; p. 197. Thin seams and layers, and nodular masses, as well as regular coal-fields of lignite, occur in the tertiary formations. At Castle Hill, near Newhaven, in Sussex (Wond. p. 239), a seam of lignite resembling the surturbrand of Iceland, a few inches thick, is interposed between strata of red marl in which are carbonized leaves of dicotyledonous trees. At Alum Bay in the Isle of Wight, a layer of lignite occurs between the beds of vertical gravel and sand of that interesting locality. Wealden Coal.—The Wealden formation, in some districts, contains layers of lignite, which alternate with finely laminated micaceous sandstones, marls, and clays, abounding in minute carbonized fragments of fern-leaves, with fresh- water shells, and entomostracous crustaceans. This series of strata so strikingly resembles in its general aspect the characters of a coal-field, that some years since extensive works were undertaken in Sussex, in the expectation that coal might be obtained of suitable quality for economical purposes. The search was unsuccessful, but the attempt deserves not the censure that was bestowed upon it, in the infancy of geological science;[48] for experience has since shown, that although the true coal-measures are only found beneath the Triassic and Permian formations, good combustible bituminous coal is not necessarily restricted to any period or series of strata, but may occur wherever the local conditions were favourable to the accumulation and bituminization of vegetable matter. In fact, the coal-fields of the north of Germany are of the Wealden epoch; and this coal more closely approaches in its chemical characters the black-coal of the ancient carboniferous formations, than any of the lignites and brown-coals of the tertiary strata. Some of the beds are highly bituminous, especially those of Schaumberg, and of the principality of Bückeburg, which may rank with the best English Newcastle coal; but those layers which are derived from coniferous trees and plants are more laminated, and somewhat resemble the brown-coal. These deposits have originated for the most part from
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