472 gp:ological survey of the territories. 



2. Ostrea Small speoimens, of perhaps two or 



three species. 



3. Grypluva A small species of form of the G. 



(lilatafa. 



4. Camptoneetes Specimen imperfect ; may be G. 



bellistriata, M. aud H. 



5. Pecten Part of a valve of a rather large, 



strougly costate species. Not a 

 true typical Pecten. 



6. Pinna Near P. opalina, Quenstedt. 



7. Gervillia Montanccnsis, Meek.* 



8. GcrinlUa v . . Somewhat larger than the last, but 



not costate. 



9. MytUns . . ' Has angular umbonal slopes, and 



only concentric markings. 



10. Modlola ( Vulsella) sublmbricata, 



Meek.t 



11. Modiola ( Vulsella) A shorter, wider, and less arcuate 



si)ecies than the last. 



12. Trigonia Americana, Meek.l 



13. Triyonia Monfanaensis, Meek.§ 



14. CrassateUa (?) It has the external appearance of 



this genus, but may belong to 

 some other. 



15. CrassateUa (?) Internal casts apparently of species 



of this genus. 

 IG. CiiculUva Casts. 



17. Astarie (?) - A small shell like some of the Juras- 



sic species sometimes referred to 

 this genus. 



18. TJnicardium " Casts apparently of a species of this 



genus. 



19. Myacites {Pleuromya) subcom- 



pressa,Meek.\\ 



# 



* A medium-sized, very obliqne species, with posterior ear flattened and of moderate 

 size, angular at the extremity, and equaling, on the hinge line, about half the length 

 of the valves ; body portion of the Valves rather slender, nearly straight, or a little 

 arched, ranging at an angle of 28*^ to 30° below the hinge line, in the left valve con- 

 vex, in the right flattened, or less convex than in the other. Surface of both valves 

 marked by tine concentric strife, and a few stronger furrows of growth, crossed on the 

 body part of the left valve, by a few slender radiating costal, separated by wider 

 spaces. 



tThis is very like Modiola imhrir.ata, Sowerby, as illustrated by Morris and Lycett, in 

 their Monogr."^ Moll. Gr. Oolite, PI. IV, Fig. 2, excepting that its anterior ventral por- 

 tion, in front of the umbonal ridges, is more prominent, and its posterior basal extrem- 

 ity more produced and narrowed. It is much less like Sowerby's original ligure of 

 that spe(;ies. 



t A tine species of the type of T. costata of the Old World, but diflering from that and 

 the other allied forms, in "having the radiating costie of the corselet, or posterior dorsal 

 region, all of uniform size. 



^ Of the type of T. sujnafa, Agassiz, but differing in its proportionally shorter form, 

 with .suiiilleV nodiferous costa', while it has a row of nodes down the anterior lateral 

 region of each valve, nearly as in T. lumn, Lamarck. 



II Resembles some varieties of FJcuromyaferniginca and I'.impre^sa, Agassiz, but has the 

 anterior end shorter and more truncated, the concentric ridges of less regularity, and tho 

 slight concavity extending from the beaks to the anterior basal margins of the valve-s, 

 either entirely wnnting or very feebly marked. I have fully described aud illustrated 

 this shell in the unpublished paleoutological part of Mr. King's rejtort. 



