64 



Description of New Species of Pisidium. 



Calamine, . 



Brochantite, 



Cotunnite, . 



Haidingerite, 



Gothite, 



Polycrase, . 



Valentinite, 



In Yalentinite this relation is evidently dependent on the 

 more authoritative and equally exact ratio a : b : c=l :-/3 : VlT 



Many conclusions bearing on chemical formulas, and the che- 

 mical relation of species, flow from the facts in the preceding 

 tables. But we leave, for the present, that branch of the sub- 

 ject without further remarks. 



IX. — Descriptions of Three New /Species o/Pisidium. 



By Temple Peimk. Read September 5, 1853. 



l. Pisidium cicer. 



CABINET OF THE DESCRIBEE. 



Plate I. Fig. 1, a, b, e. 



Shell medium sized, much inflated, rather short, thick and 

 heavy ; beaks not large but prominent ; posterior margin some- 

 what abrupt. Striae light. Epidermis glossy. Anterior mar- 

 gin abrupt from the beaks downwards. Color brownish green. 

 Interior blue. Length 0.25, Breadth 0.23, Diam. 0.12 inches. 



Habitat. — Washington County, N. Y. (Ingalls.) 



