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 ujoper from Coalville, it is not possible to say to what extent this 

 shell may vary. If distinct from 0. Wyomim/ensis, it might be called 0. 

 Coalvillensis. 



Locality and position. — Coalville, Utah; Cretaceous. 



ANOMIID^. 



ANOJIIA E^TiTIFORMIS, Meek. 



Sht'll of well-developed specimens transversely subovate, generally more 



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



and rather narrowly rounded on the i-ight margin, with 



the pallial margin between semiovate in outline; upper 



\ ;dve moderately convex, the greatest convexity being 



tuward the left margin, while the narrowly-rounded 



right margin is more compressed and produced; beak 



marginal, nearly central, with generally a slight curva- 



Cabtrrupp'e'r \aiv",''nat- turo towurd the right; surface showing small, obscure 



wrinkles and stria? of growth, witli sometimes traces of 



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



lower valve unknown. 



Greatest (transverse) diameter, 1.2G inches; diameter from beak to pallial 

 margin, 1.12 inches; convexity of u^^per valve, aboixt 0.30 inch. 



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

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

 rig-ht (posterior) margin. The younger specimens are generally more nearly 

 circular in form. 



I know of no other Cretaceous species of tlie 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. 



