FOSSILS OF THE DEVONIAN. 



137 



Spirifera Parryana Hall? 

 Plate xiv, fig. 10. 



Spirifer parryanus Hall, 1858. Geology of Iowa, vol. i, pt. 2, p. 509, pi. iv, figs. 8 a, 6. 

 Parryana Billings, 1861. Can. Jour., vol. vi, p. 261, figs. 77, 78. 



The original type of this species is from the Hamilton Group of Iowa. 

 In all essential specific characters the ventral valve of the Nevada shell, 

 the only portion discovered, is similar to that of the Iowa type, differing 

 mainly in the absence of the fine concentric strise crossing the radiating 

 strise. Each of these features, the simple radiating strise and the concentric 

 striae, occur on different specimens of an allied species, 8. mesastrialis, of the 

 Chemung Group of New York. The finding of entire shells may afford 

 specific distinctions not known at present, but with the present specimens, 

 the identification is made with S. Parryana. 



A specimen collected by the geologists of the Fortieth Parallel Geo- 

 logical Survey, labeled "Piiion Range," is larger than the Eureka specimens, 

 but otherwise agrees with the specimen illustrated. 



Formation and locality. Devonian limestone, on the divide at the head 

 of the Reese and Berry Cafion, Eureka District, Nevada. 



Spirifera (sp. und't.). 



This species is allied to the group represented by Spirifera Manni, of 

 the Upper Helderberg Group of New York and Ohio. The ventral valve is 

 subpyramidal, the height nearly equaling one-half the length. Apex slightly 

 projecting over the area. Mesial sinus well-defined, reaching to the apex. 

 Area elevated, slightly concave above; fissure open to the apex, about twice 

 as long on the sides as the width at the base. 



Surface marked by six or seven subangular or rounded plications on 

 each side of the median sinus. Finer surface markings unknown, owing to 

 the exfoliation of the shell. 



Owing to the fact that species of this genus undergo great variations, and 

 that our material is unsatisfactory, no specific reference is made of this shell. 



Formation and localities. Devonian limestone, Comb's Peak, Eureka 

 District, and Lone Mountain, 18 miles northwest of Eureka, Nevada. 



