FOSSILS OF THE DEVONIAN. 



191 



This and the preceding species have slight indications of uninterrupted 

 concentric lines of growth, so that the generic reference will probably be 

 sustained on the finding of more perfect specimens. They are large, robust 

 forms, differing very much from each other and from any described species 

 occurring at the same geologic horizon. 



Formation and locality. Lower horizon of the Devonian limestone, 

 Comb's Mountain, Eureka District, Nevada, 



Loxonema ? subattenuatum Hall ? 



Lojconema subattemiata Hall, 1861. Descriptions of New Species of Fossils, etc., p. 24. 

 Mem., 1862. Fifteenth Aun. Rep. N. Y. State Cab. Nat. Hist, p. 52. Idem., 

 1876. Pal. N. Y., Illustrations of Devonian Fossils, Gasteropoda, pi. xiii, 

 figs. 1-3. Idem., 1879. Pal. N. Y., vol. v, pt, 2, p. 40, pi. xiii, figs. 1-6. 



The illustrations of this species in the Paleontology of New York do 

 not show the surface characters, which restricts the comparison to the casts; 

 ^imong these the differences between the two, L. subattenuatum and the Ne- 

 vada form, are so slight as to make it impossible to separate them on good 

 specific characters. 



The species occurs at Comb's Peak, in the Lower Devonian, and at the 

 same relative horizon in Gray's Canon, Eureka District, Nevada. 



Loxonema approximatum, u. sp. 

 Plate vi, fig. 7. 



Shell, terebriforrn; spire rapidly ascending, volutions slightly convex, 

 increasing regularly from the apex, the last one a little vertical; six in the 

 length of 2J inches from the base. Aperture subelliptical. 



Surface as shown on the inner cast, marked by moderately strong, not 

 closely arranged, longitudinal striae that are nearly transverse to the volu- 

 tions ; the .striae arch backward very slightly. 



The description of this species is nearly identical with that of Loxone- 

 ma styliola Hall (Pal. N. Y., vol. v, pt. y, p 48, pi. xiv, figs. 8, y) from the 

 Chemung Group of New York. It differs only in the more elongate form 



