WHAT EVOLUTION IS 41 



vated and depressed, and that what 

 was once sea bottom, with its myriads 

 of marine plants and animals, might 

 well become mountainside with its 

 contained fossils. Gradually the 

 opinion grew that all fossils were the 

 remains of once living organisms, 

 and this doctrine, advanced through 

 the efforts of such workers as Fra- 

 castoro, Steno, Hooke, and others, 

 had gained complete acceptance in 

 the days when Lamarck (1744- 1829) 

 and Cuvier (i 769-1 832) were found- 

 ing modern paleontology. 



Concurrent with the growth of the 

 new ideas about fossils came the con- 

 ceptions of stratigraphic geology. 

 Rocks not only contain the fossil re- 

 mains of once living organisms, but 

 the underlying rocks hold remains of 

 an older date than do those above 

 them. Such a sequence of fossils, as 

 is implied by this view, was advocated 



