The Lake Tahoe basin was formed 2-3 million years ago by geologic block faulting which caused chunks of land to drop down and form a basin. This basin eventually filled with water from snow, rain and streams to form the ancestral Lake Tahoe. Modern Lake Tahoe was then shaped by glaciers during the ice age. The primary rock found in the basin is granite, an igneous rock formed from cooled magma. Animals commonly seen around Lake Tahoe include bald eagles, raccoons, and the flowering Shasta daisy is a prominent plant.