MODERN BIOLOGY 455 



done by some of his friends, but he had a keen eye to the place into which 

 each form should fall in the strata system. Eventually he published the 

 results of his life-work in a great geological atlas of England, which cost 

 him his whole fortune. For a time he suffered want, but was eventually 

 granted a government pension, which ensured him a peaceful old age. It 

 was through him that the use of guiding fossils for identifying the age of 

 geological formations was introduced into science. 



An investigator who surveyed, and in a high degree developed, the 

 geological knowledge of his age was Christian Leopold von Buch (1774- 

 1853). He belonged to a distinguished and wealthy Prussian family, and 

 studied under Werner at Freiberg together with Humboldt with a view to 

 entering the mining service, but he soon applied himself entirely to geology, 

 which, thanks to his inherited wealth, he was able to study without having 

 to earn his living. He made extensive expeditions, in the course of which 

 he made a particularly fine collection of comparative material from various 

 countries. The result of this research work soon led him from the Neptun- 

 ism of Werner to the opposite extreme; he ascribed to volcanic activity an 

 important, and indeed far too important, part in the history of the earth's 

 surface. His investigations, carried out in different regions, are nevertheless 

 of lasting value; he w^as, moreover, an eminent palaeontologist, making 

 valuable investigations of special subjects, particularly of fossil inverte- 

 brates: Cephalopoda, Brachiopoda, and others. 



Charles Lyell is, however, the scientist that is first worthy of mention 

 as the founder of modern geology and thereby as a pioneer of the descent 

 theory. He was born in 1797, the son of a Scottish landowner, who was also 

 interested in botany and who inspired in his son a passion for nature study. 

 The latter took his degree at Oxford and afterwards adopted the profession 

 of a lawyer. But he did not go far in that career, for eye-trouble compelled 

 him to give up public work of any kind. Long before this, however, geology 

 had attracted him, W. Smith's investigations especially interesting him, and 

 for the rest of his life he devoted himself to that study, bearing with un- 

 paralleled courage the severe deprivation that defective vision always means 

 to a scientist, especially a natural scientist. One source of comfort in these 

 circumstances was the fact that his wife with devoted self-sacrifice dedicated 

 her life to helping him in his work. He thus became one of the many bril- 

 liant private scholars in which the cultural history of England abounds, and 

 he was the recipient of not a few honours. He undertook a number of long 

 voyages of exploration; he considered them to be indispensable for a geol- 

 ogist, for it is only thus that he can gain that living idea of the various 

 forms of the earth's surface which may serve as a basis for a theory of its 

 history. The rest of his time he spent in London, where he was a member of 

 many learned societies and was also otherwise held in high repute. He died 



