112 PALEONTOLOGY OF THE EUREKA DISTRICT. 
Genus DISCINA Lamarck. 
Discina minuta Hall. 
Plate xiii, fig 5. 
Orbicula minuta Hall, 1843. Geol. Rep. Fourth District of New York, p. 180. 
Discina minuta Hall, 1867. Pal. N. Y., vol. iv, p. 16, pl. i, fig. 16 ab. 
This small and pretty species is represented by a number of examples 
that correspond closely with the typical specimens from the Marcellus shale 
of New York, and which are considered identical with them, although 
separated by a distance of 1,800 miles, and occurring at a different horizon 
in the Devonian Group. 
The New York specimens vary from 1.5™™ to 4™™ in diameter, while 
the largest from Nevada is 4™™ in its greater diameter, and of about the 
same convexity as examples of the same size from New York. 
Formation and locality—Upper horizon of the Devonian limestone, at 
The Gate, northeast of Eureka, Nevada. 
Discina, sp. (?) 
Considerable interest is attached to this shell, as it is very rare and 
the only species of the genus from the Lower Devonian of the Rocky 
Mountain area, but one imperfect specimen showing the two valves united 
occurs in the collections. In general form it is not unlike Discina media of 
the Hamilton Group of New York. 
Formation and locality—Lower Devonian of Lone Mountain, 18 miles 
northwest of Eureka, Nevada. 
Discina Lodensis Hall. 
Plate ii, figs. 5, 5a. 
Orbicula lodensis Hall, 1843. Geol. Rep. Fourth Dist. N. Y., p. 223. 
lodensis Vanuxem, 1842. Geol. Rep. Third Dist. N: Y., p. 168. (Wood cut 
used in advance of publication of the Report on the Fourth District.) 
Discina lodensis Hall, 1867. Pal. N. Y., vol. iv, p. 22, pl. i, figs 14 a-f; pl. ii, fig. 35. 
lodensis Rathbun, 1874. Bull. Buffalo Soc. Nat. Sci., vol. ii, p. 257. Ibid., 1878 
Proc. Boston Soc. Nat. Hist., vol. xx, p. 17. 
Compare D. media Hall, 1857. Pal. N. Y., vol. iv, p. 20, pl. ii, figs. 25-28. 
