70 



TITANOTHEEES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



FiGUHE 46. — Composite section of the Eocene deposits of tlie Big Horn and Clark Fork Basins, Wyo. 



This section contains ttie entire Big Horn Basin Wasatch of Cope's descriptions, which is now divided into very clearly defined 

 ascending life zones, as follows: 5, Phenacodus-Nothoiectes-Coryphodon zone; 6, EoMppus- Corijphodm zone; 7. Systemodon-Corypho- 

 don- Eohippus zone; 8, Heplodon- Coryphadon-Eohippus zone; 9, Lambdotliermm-Eotitanops-Coryphodon zone. A few characteristic 

 species of mammals from each horizon are indicated in the right-hand column. Chiefly after Granger (1918). 



