186 



POPULATIONS OF THE SEA 



X Known distribution of the 

 early Turonian ammonite 

 Sciponoceras gracile I 

 (Shumard) 



126 



108 



90 



72 



Fig. 10. Early Late Crustaceous (Turonian) seaway through Rocky Mountain 

 geosyncline with inferred current patterns assuming no latitudinal change (shore- 

 lines adapted from Schuchcrt, 1955, map 73, and \\'oodring, 1954, Fig. 1). 



