3(5 PALEONTOLOGY. 



with the shell mostly exfoliated, this form seems to agree well with the 

 above-cited New York species, as may be seen by comparing our figure with 

 fig. 2, pi. 9, of the 4th vol. N. Y. Palaeontology. It is quite possible, how- 

 ever, that a direct comparison with New York specimens might show it to 

 be distinct. I do not feel justifiable, however, without a good series of 

 specimens from the two distantly-separated localities for comparison, in run- 

 ning the risk of further complicating the synonymy of a species that has 

 already received so many names, and consequently prefer to refer it to the 

 New York species, instead of attempting to name it as new. 



Locality and position. — Colonel Simpson's collection, latitude 39'^ 30' 

 N., longitude 115° 3G' W.; from dark Devonian limestone. 



PRODUCTIDJ^:. 



Genus PRODUCTUS, Sowerby. 



PuoDUCTUS SUBACULEATUS, Murcliison "I . 



Plate 3, figs. 7,7 a, 7 h. 



Prodiwtus subaeulentm, Murchisou (1840), Bull. Soc. Geol. Fr., XI, 255, pi. ii, (ig. !».— 

 De Verueuil (in i>art) (IMS), Geol. Russ. ami tlie Ural Mts., 11,282, pi. xvi, 

 fig. 9._De Koiiiuck (1847), Mem. Soc. Koy. Lit^ge, IV, 249, pL xiv, fig. 4; and 

 Monogr. Piod. and Chon., 142, pi. xvi, fig. 4.— De Vern. (1847), Bull.— Soc 

 G<5ol. Fr., 2d ser., IV, 705, pi. Ix.— Schnurr (1853), in Duuker and von 

 Meyer's PaliBont., II, 228, pi. xliii, fig. 4 «.— Davidson (1853), Quart. Jour. 

 Geol. 8oc., 336, pi. xv, fig. 12. — Sandl)erger (1855), Die Brach. Reiniscb. 

 Scliicbt. Nassau, 75, pi. xxxiv, fig. 17. — Davidson (1865), Monogr. Brit. Devon. 

 Foss., 99, pi. XX, parts 1-2.— Meek (1876), Col. Simpson's Report Expl. across 

 the Great Basin of Utah, 345, [d. i, figs. 3 a, b, c. 



Lepta-na fmgaria, Sowerby (1840), Trans. Geol. Soc. Loud., 2 ser., V, 704, pi. Ivi. fig. 

 5.— Phillips (1841), Pal. Foss., 59, pi. xxv, fig. 100. 



Leptwna {Strophalosia) snbaculeata, McCoy (1852), Brit. Pal. Foss., 388. 



Comp. P. Shitmardianus var. pyxidatus, Hall (1858), Iowa Report, I, part 2,498 and 

 499. 



Shell small, thin, truncato-subhemispherical; hinge equaling or less 

 than the gi-eatest breadth; ears small, nearly rectangular, or somewhat 

 i-ounded ; lateral margins rounding to the front, which is regularly rounded 

 in outline. Ventral valve moderately convex, the greatest convexity being 

 near the middle, without any traces of a mesial sinus; beak not very prom- 

 inent, incurved, though witliout distinctly passing within the hinge-margin; 



