FOSSILS OF THE DEVONIAN. 



171 



Modiomorpha obtusa, n. sp. 

 Plate iv, figs. 8, 8 a. 



Shell subrhomboidal in outline. General surface strongly convex, the 

 umbonal ridge rounded. Hinge-line about one-half the length of the shell. 

 Beaks small, incurved, and situated on the anterior third of the cardinal por- 

 tion of the shell. 



Surface marked by a few concentric lines of growth. Anterior muscu- 

 lar scar large, well denned; other interior characters unknown. 



Dimensions-, height, 1.5 cm ; width, 2.5 cm ; depth of right valve, 0.5 cm . 



To some of the more transverse forms of Modiomorpha quadrula Hall 

 (Pal. N. Y., vol. v, pt. 2, Plates and Explanations, pi. xli, figs. 18-26), 

 this species bears a stronger resemblance than to any other form we know. 

 It differs in the character of the umbonal ridge and the posterior extension 

 of the shell. 



Formation and locality. Lower Devonian of Brush Peak, Eureka Dis- 

 trict, Nevada, and also at the same horizon on Lone Mountain, 18 miles 

 northwest of Eureka, Nevada. 



Genus GONIOPHOBA Phillips. 



Goniophora peraugulata H. 



Plate xv, fig. 10. 



Sanguinolites perangulatus Hall, 1870. Prelim. Notice Lam. Shells, p. 35. 

 Goniophora perangulata Hall, 1883. Pal. N. Y., vol. v, pt. 1, Plates and Explanations, 

 p. 12, pi. xxxiv, figs. 1-7. 



In identifying this species a direct comparison was made between the 

 specimens from Nevada and the type specimens from the Upper Helder- 

 berg Group of New York, at the New York State Museum of Natural His- 

 tory, Albany, N. Y. No variations of specific value were observed; the 

 identification is further strengthened by the presence of Pterinea fldbetta and 

 several species of Brachiopods, that are associated with the species at each 

 locality. 



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

 northwest of Eureka, Nevada. 



