Charles Withers, Professor Emeritus University of Edinburgh and
Geographer Royal for Scotland
reading from a letter to Darwin by Lyell discussing the domestication
of the dog.
Sir Charles Lyell was a geologist whose work helped to found the modern
notion of geology and geologic time whilst establishing geology as a
separate science. In his first book, Principles of Geology, (1830) he
propounded his theory of uniformitarianism, that the Earth's history can
be explained by gradual change over time. He also proposed the idea
that different periods of geologic time could be established by
reference fossils, he divided geologic time into four periods;
Pleistoscene, Older Pliocene, Miocene and Eocene. He also expounded
notions on the rock cycle, how one type of rock was transformed into
another, volcanic forces, deposition and erosion.