166 PALEONTOLOGY OF THE ETJEEKA DISTRICT. 



Left valve unknown. 



Dimensions : length of shell, 4.5 cm ; width the same. 



This species is closely related to Pterinea Chemungensis Conrad (PaL 

 N. Y., vol. v, pt. 1, p. 98, 1884) from the Devonian of New York. It differs 

 in the more anterior position of the beak and less elongate outline. 



Formation and locality. Upper Devonian of Newark Mountain, Eureka 

 District, Nevada. 



Genus ACTINOPTERIA Hall. 



Actinopteria Boydi Conrad (Sp.). 

 Plate v, fig. 2. 



Avicula Boydii Conrad, 1842. Jour. Acad. Nat. Sci. Philad., vol. viii, p. 237, pi. xii, fig. 4. 



Pterinea Boydi Miller, 1877. Cat. Amer. Pal. Fossils, 2d ed., p. 201. 



Actinoptera Boydi Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explanations, p. 8; 



pi. xix, figs. 2-24. 

 Actinopteria Boydi Hall, 1884. Pal. N. Y., vol. v, pt. 1, p. 113. 



There is only a single left valve of this species in the collection, and 

 that is somewhat distorted by pressure. A direct comparison with authentic 

 specimens from the Hamilton Group of New York shows such a striking 

 similarity between them and the Nevada shell that there is little hesitancy 

 in identifying the species by the one specimen. 



Formation and locality. Lower Devonian of Lone Mountain, 18 miles 

 northwest of Eureka, Nevada. 



Genus LEIOPTEKIA Hall. 



Leiopteria Rafinesquii Hall. 

 Plate v, figs. 10, 10 a. 



Leiopteria Bqfinesquii Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explanations, pp. 

 7, 9; pi. xv, fig. 11; pi. xx, figs. 6, 7. Ibid., 1884, text, p. 161. 



The examples of this species from Nevada embrace both the Upper 

 Helderberg and Hamilton Group forms, as illustrated in the Paleontology 

 of New York. The identification is made with the figures, as we have no 

 typical specimens of the species for comparison. 



Formation and locality. Lower Devonian of Brush Peak and Atrypa 

 Peak, Eureka District, Nevada. 



