EVIDENCES— GEOLOGY 143 



addition of more and more complex organisms to the population 

 of the earth has occurred as time has passed. The succession cor- 

 responds to the major sequence of existing phyla and even within 

 minor groups is often a valuable indication of phylogeny. 



REFERENCES 



Von Zittel, K. A., Textbook of Palaeontology, translated by Eastman, C. R., 



1900. 

 Scott, D. H., The Evolution of Plants, 1911. 

 Thomson, J. A., Outline of Zoology, 6th edition, 1914. 

 Lull, R. S., OrgaJiic Evolution, 1917. 



Lull, R. S. (editor). Evolution of the Earth and Its Inhabitants, 1918. 

 Handlirsch, a., Schroder's Handbuch der Entomologie, 1925. 

 Knowlton, F. H., Plants of the Past, 1927. 



