Grabau — Faunas of the Hamilton Gp.oup. 



245 



PTEROPODA. 



Genus Tentaculites, Schlotheim. 



13. Tentaculites bellulus, Hall. 



1879, Hall, Pal. N. Y., vol. 5, pt. 2, p. 169, pi, 31, 31a. 



1 nave found this species as low as fourteen feet below the Encrinal lime- 

 stone. It usually occurs as isolated individuals, though a fragment of shale con- 

 taining four individuals was found in the Strqpheodonta demissa bed. None of 

 the specimens show the apex, but all show the annulations and the concentric 

 striae. The length of the largest specimen is about IT mm. An impression 

 in shale from the upper part of the Moscow beds is doubtfully referred to 

 this species. 



14. Tentaculites gracjustriatus, Hall. 



1879, Hall, Pal. N. Y., vol. 5, pt. 2, p. 173, pi. 31, 31a. 



In 1879, Professor Hall wrote; * " the latter form \T. grddlisi^iatus] 

 is at present unknown in the centre of the Hamilton group or in any higher 

 position; the Styliola [Styliolina] alone so far as known being present in the 

 superior strata." In 1885, J. M. Clarke f described this species from the 

 Genesee and Naples shales of Ontario county, N. Y., where it is associated 

 with StylioUna fissurella. 



I have found several specimens in the Stropheodonta demissa 

 bed, also a large number in the upper part of the Moscow shales. 

 At Section F, Eighteen-mile creek, about two feet below the Styliolina 

 band, occurs a thin layer of shale, less than half an inch in thickness, in 

 which this little shell occurs to the exclusion of almost every other form. 

 No Styliolinas have been observed, though in the lower beds the two are 

 associated. The specimens are usually found crushed and may at first be 

 taken for Styliolina fissurella. The annulations however are shown on all 

 the specimens, but the longitudinal striae do not always appear. The species 

 also occurs in the shale four feet below the Encrinal limestone at Section C, 

 where it is associated with S. jissurella. I have found it as low as the 

 Trilobite beds, where it is rare and associated with the species next enumerated. 

 It does not occur again until we reach the Marcellus shale in the upper beds 

 of which it is a common form. 



* Pal. N. T. vol. 5. pt. 2, p. 177. 

 t Bull. U. S. Geol. Surv. No. 16. 



