CRETACEOUS FOSSILS. 141 



locality more strongly crenate or transversely striated than I have yet seen 

 in any example of the Wyoming shell. As I have only two lower valves 

 and one upper from Coalville, it is not possible to say to what extent this 

 shell may vary. If distinct from 0. Wyomingensis, it might be called 0. 

 Coalvillensis. 



Locality and position. — Coalville, Utah; Cretaceous. 



ANOMIID^. 



Anomia r^tifokmis, Meek. 



Shell of well-developed specimens tran&versely subovate, generally more 

 broadly rounded on the left side (as seen from above), 

 and rather narrowly rounded on the right margin, with 

 the pallial margin between semiovate in outline; upper 

 valve moderately convex, the greatest convexity being 

 toward the left margin, while the narrowly-rounded 

 right margin is more compressed and produced; beak 

 marginal, nearly central, with generally a slight curva- 



Anomia 1-wHformis. , , ,,, -i, n i • ni 



Cast of upper valve, nat- ture toward the right; surface showmg small, obscure 

 wrinkles and striae of growth, with sometimes traces of 

 a few indistinct radiating markings on the most convex part of the umbo; 

 lower valve unknown. 



Greatest (transverse) diameter, 1.26 inches; diameter from beak to pallial 

 margin, 1.12 inches; convexity of upper valve, about 0.30 inch. 



This species presents, in the well-developed adult, a singular Rceta- 

 like form, being narrowed and subrostrate, or more or less produced on the 

 right (posterior) margin. The younger specimens are generally more nearly 

 circular in form. 



I know of no other Cretaceous species of the genus very nearly allied 

 to this. 



Locality and position. — Ridge southeast of Laporte, Colorado Territory; 

 Cretaceous. Horizon of the Fox Hills Group of the Upper Missouri section. 



