GASTEROPODA. 41 



This is a larger and more elongate species than any other of the genus in 

 the Upper Helderberg rocks. The specimens are casts of the interior, rarely 

 showing surface markings; but from the general character of the fossil, the 

 moderately convex volutions and close suture-line, it may be recognized as 

 belonging to the genus Loxonema. 



This form is more gradually tapering, while the spire is more rapidly ascend- 

 ing than in L. subattenuata, and the exterior of the volution is a little more 

 convex than the usual form of that species. A single specimen from the lime- 

 stone at Clarence Hollow, in Erie county (fig. 6), bears the same proportions 

 as those from the Schoharie grit in the eastern part of the State. The shell, 

 when entire, has been nearly four inches long. 



Formations and localities. In the Schoharie grit at Schoharie; and in the 

 limestone of the Upper Helderberg group at Clarence Hollow, Erie county, N. Y. 



Loxonema solida. 



PLATE XUI, FIGS. 8, 9. 



Loxonema solida, Hall. Descriptions of New Species of Fossils, etc., p. 23. 1S61. 



" >• " Fifteenth Rep. N. Y. State Cab. Nat. Hist., p. 51, pi. 4, fig. 6. 1862. 



•« " " Illustrations of Devonian Fossils : Gasteropoda, pi. 13. 1876. 



Shell turretiform, elongate ; spire gradually ascending. Volutions moderately 

 convex, the height of each one about half the diameter of the spire at the 

 same point. 



In a specimen of moderate size, five volutions from near the base measure a 

 little more than one inch in vertical height. This species, in its form and 

 proportions, is intermediate between the L. compacta and the L. obtusa of the 

 Lower Helderberg group, the volutions being slightly more convex than in 

 either of these. The specimens are all casts of the interior, and are incom- 

 plete both at base and summit, and can only be distinguished by the form and 

 proportions of the volutions. 



Formation and locality. In the Schoharie grit at Schoharie, N. Y. 

 6 ' 



