124 PALEONTOLOGY OF THE EUREKA DISTRICT. 
Chonetes deflecta Hall. 
Plate ii, figs. 8, 8 a, b. 
Ohonetes deflecta Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 149. 
gibbosa Hall, 1857. Ibid., p. 145. 
deflecta Hall, 1867. Pal. N. Y., vol. iv, p. 126, pl. xxi, figs. Ta-g, 8a-c. 
The shells referred to this species are from the Upper and Lower De- 
vonian beds, and in size, general form, convexity and surface markings are 
specifically identical with the examples of the species from the Hamilton 
Group of New York. There is considerable difference in the height and 
width of different shells, and also in the strength of the radiating surface 
strie. In the latter variation Chonetes acutiradiata Hall is directly connected 
with C. deflecta, as expressed in its more transverse forms. Some of the 
more coarsely striated examples approach C. mucronata, but not sufficiently 
so to be identified with that species. 
Its vertical range is from the Lower Devonian=Upper Helderberg 
Group of New York, to the Upper Devonian=Chemung Group of New 
York. 
Formation and localities.—Lower horizon of the Devonian limestone, 
Comb’s Peak, west slope of County Peak, and lower beds at Lone Mount- 
ain, 18 miles northwest of Eureka, Upper Devonian of Rescue Hill, Eureka 
District, Nevada. 
Chonetes mucronata Hall? 
Strophomena mucronata Hall, 1843. Geol. Rep. Fourth District New York, p 181 and p. 
180, fig. 3. 
Chonetes laticosta Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 119. 
mucronata Hall, 1867. Pal. N. Y., vol. iv, p. 124, pls. xx, xxi. 
Nicholson, 1873. Pal. Prov. Ontario, p. 74. 
Professor Hall gave the specific designation C. Jaticosta to a small, gib- 
bous, coarsely striated shell from the Upper Helderberg and Hamilton 
Groups of New York, which he subsequently considered as a variety of 
Chonetes mucronata. With this form the Nevada specimens are identified, as 
none of the larger, more finely striated examples are yet known from the 
Rocky Mountain area. 
