FOSSILS OF THE DEVONIAN.. 



165 



From the results obtained by a few days' collecting at the Lower 

 Devonian horizon, there is little doubt but that by a more extended search 

 the number of species could be greatly increased over the twenty-seven 

 now known from that horizon. 



One species, Paracyclas occidentalis, passes from the lower to the upper 

 horizon, and unites with the eight species occurring there to make a total 

 of nine species occurring in a horizon stratigraphically equivalent to that of 

 the Chemung Group of New York. 



Genus PTERINEA Goldfuss. 



Pterinea flabella Conrad (Sp.). 

 Plate xv, fig. 12; pi. v, fig. 6. 



Avicula flabella Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 238, pi. 12, fig. 8. 

 Pterinea flabellum Hall & Whitfield, 1872. Twenty-fourth Ann. Kep. N. T. State 



Museum Nat. Hist., p. 199. 

 Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explanations, p. 7j 



pi. xiv, figs. 1-21 ; pi. xv, figs. 1, 4, 5, 8-10. Ibid., 1884, Text, p. 93. 



This species, which in Ohio and New York ranges from the Upper 

 Helderberg to the Chemung Groups, is found only at the Lower Devonian 

 horizon of Lone Mountain, 18 miles northwest of Eureka, Nevada. 



The specimen illustrated shows the characteristic form, and is similar 

 to that from the typical localities in the Hamilton Group of New York. 



Pterinea Newarkensis, n. sp. 

 Plate v, fig. 12. 



General form broadly truncate, suboval; length and breadth subequal; 

 cardinal margin straight, nearly if not quite equaling the greatest width of 

 the valves. 



The right valve is depressed, slightly convex at the umbonal region; 

 beak depressed; anterior surface of posterior wing marked by a few linear, 

 radiating lines, the body of the shell showing only a few concentric lines 

 of growth. The posterior muscular scar is oval in form and quite shallow. 



