300 DESCRIPTION OF A COLLECTION OF FOSSILS, 



E.? sp. indet. 



Another shell, resembling this genus, but with all the finer details destroyed 

 by crystals of carbonate of lime, which has completely replaced the shell, leaving 

 only the external form and the coarser details of the ambulacra. It is from the 

 Liassic locality of the Cerro del Ventanillo. 



BOTRIOPYGUS, d'Orb. 

 B. ELEVATUS, n. s., PI. 43, fig. 1, la. 



Shell very rounded subpentagonal, slightly narrowed in front and produced in 

 the middle behind; broadly convex above, concave below; details of ornament of 

 upper surface unknown ; lower surface closely studded with small tubercles. 



Figures. Natural size. 



Locality. From the Cretaceous table, two leagues from Cajamarca. 



B. COMPRESSTJS, n. s., PL 43, fig. 2, 2a. 



Shell broadly elliptical, ends equal; upper surface very broadly convex; under, 

 slightly concave ; details of surface ornament unknown. 



Figures. Natural size. 



Locality. Near Galea, a few leagues south of Chachapoyas. Cretaceous. 



Remarks. This species is larger than the preceding, and differs in being flatter, 

 broader, and regularly elliptical. In that, the anterior end is narrower than the 

 posterior, and the region of the anal opening is prominent; whereas in this, both 

 ends are of the same shape and width. 



DISCOIDBA, Gray. 



D. NUMiSMALis, n. s., PI. 43, fig. 3, 3a, 3b. 



Shell faintly pentagular, very depressed, apex slightly elevated, surface sloping 

 straight, or a little concavely and then convexly to the margin ; under surface 

 concave; anal opening large, elongate. Surface marked by numerous small, regu- 

 larly placed tubercles, scattered uniformly; larger and more scattered on the under 

 side. 



Figures. Natural size. 



Locality. " Cattle estate of Yauca, at the foot of the perpetual snow, one league 

 and a half from the town of Queropalca, Prov. of Huamalies ; height of 4000 

 metres." Marked " Cretaceous"?" 



Associated with this is a smaller specimen of the same genus, but apparently 

 another species. The surface has been rubbed smooth and the centre bored so as 

 to enable it to be used as a bead. It is marked 1000 metres higher, same vicinity. 



