STRATIGRAPHIC CLASSIFICATION 569 



With a better knowledge of the physical geography of the 

 globe at successive epochs we may more hopefully attack the 

 great problems of mountain growth, continental development, 

 and earth dynamics. But our first work is to map the lithologic 

 individuals, while our associates, the paleontologists, distinguish 

 the faunal units of stratigraphy. 



Bailey Willis. 



