PCSSILS OF THE DEVONIAN. 147 



Formation and localities. Middle and Upper Devonian limestone, Tele- 

 graph Peak, and eastern base of Mount Argyle, White Pine Mining District, 

 Nevada. 



Cyrtina Hamiltonensis Hall. 



Cyrtia hamiltonensis Hall, 1857. Tenth Arm. Eep. N. Y. State Cab. Nat. Hist, p. 166. 

 Hamiltonensis Billings, 18G1. Canadian Journal, n. ser., vol. vi, p. 262, figs. 



80-82. Geol. Canada, 1863, p. 384, figs. 415 a-c. 

 Cyrtina hamiltonensis Hall, 18G7. Pal. N. Y., vol. iv, p. 268, pi. xxvii, figs. 1-4; pi. xliv, 



figs. 26-33, 38-52. 

 Hamiltonensis Meek, 1869. Trans. Chicago Acad.Sci., vol. i, p. 99, pi. xiv, figs. 



5, 7, and 10. 



Hamiltonensis Nicholson, 1874. Eep. Pal. Prov. Ontario, p. 83. 

 Compare Cyrtina heteroclita of authors. 



The only specimen of this species recognized in the Eureka District 

 collection is from the Upper Devonian horizon; it is a silicified shell pre- 

 serving the two valves united, and below the average size of full grown 

 individuals from the Hamilton Group of New York and Canada; there 

 appears to be little question of its specific identity with them. 



In the collection of Devonian fossils from the Mackenzie River, Brit- 

 ish America, Mr. F. B. Meek recognized this species (Trans. Chicago Acad. 

 Sci., vol. i, p. 100), and he also states that it occurs on Porcupine River, a 

 tributary of the Yukon, longitude 140 W., latitude 67 N. 



Formation and locality. Upper Devonian, at The Gate, northwest of 

 Eureka, Nevada. 



Genus NUCLEOSPIEA Hall. 

 Nucleospira coucinna Hall. 



Atrypa concinna Hall, 1843. Geol. Eep. Fourth District New York, p. 200, fig. 3. 

 Nucleospira concinna Hall, 1859. Twelfth Ann. Eep. N. Y. State Cab. Nat. Hist., pp. 25 

 and 26. Hid., Hall, 1867. Pal. N. Y., vol. iv, p. 279, pi. xlv, figs. 33 to 57. 



This species is a rare form in Nevada, having been found but sparingly 

 at one locality. At the East it has a wide geographic range in the State 

 of New York, and is also found in the States of Virginia, Maryland, and 



Indiana. It ranges vertically from the Schoharie grit up into the Hamilton 

 Group. 



Formation and locality. Lower horizon of the Devonian limestone, 

 Lone Mountain, northwest of the Eureka District, Nevada. 



