Paleontology Zorritos Formation 125 



they are irregular and more widely spaced near the beaks. 

 Upper Zorritos. Quebrada del Toro. 



Area (Anadara) toroensis var. prolata n. var. 

 Plate VII— Fig. 3. 



Shell high, thick, inflated. Characters as in A. toroensis 

 with the following exceptions : Beaks narrow and pointed, 

 much higher than in toroeitsis. Area very high in propor- 

 tion to length, covered with many fine longitudinal grooves 

 which grow more distantly separated toward the beak. Either 

 symmetrical in shape or slightly produced posteriorly; not 

 distinctly so as is toroensis. 



The separation from the typical toroensis presents much 

 the same sort of problem as that offered by the variety 

 crassa; the points of difference would have specific value but 

 for an intergradation. Its differentiation is advisable on 

 account of the wide variation in shape and general appear- 

 ance. However, its clear relationship to the parent species 

 indicates the sub-specific nature of the differences. 



Upper Zorritos. Quebrada del Toro. 



Superfamily Pectin acea 



Family PECTINIDAE 



Genus Pecten Miiller 



Pecten zcoodringi n. sp. 



Plate VII — Figs. 4, 5. 



Pecten sp. indet. Xelson, Trans. Conn. Acad., vol. 2, p. 205, 

 1870 (ex parte). 



Shell small, slightly inequivalve, the left valve more con- 

 vex, subequilateral. The right valve somewhat flattened, 

 with about 15 round ribs, arranged in fan shape, a little 

 wider than the interspaces. Submargins steep, smooth, flat ; 

 anterior ear with four distinct radiating ribs, crossed by 



