Igg PALEONTOLOGY OF NEW YORK. 



from accident. The surface-marking is subject to considerable degree of varia- 

 tion in the strength of the annulations, which are sometimes sharp elevated 

 ring!, and are variable in their distance from each other, while in other parts of 

 the same specimen they are reduced to fine stria). In two specimens only, are 

 we able to observe what appears to be the position of the ventral line ; but 

 there is no evidence of a groove or interruption of the striae, except where the 

 specimen has been compressed, and this groove is apparently the result of a 

 fracture of the shell. In another part of one of the specimens tbus marked, 

 the annulating stria? converge towards the apical extremity, but are continuous 

 across the body of the shell, as shown in figure 8 of plate XXXII A. 



At the present time I see no reason for separating the form found at the 

 Falls of the Ohio from those of the Hamilton shales in New York. The latter 

 is usually stronger and always rigidly straight; the annulations, where well 

 preserved, are sharply elevated and present the characters of the best preserved 

 specimens in New York. Among a considerable number of specimens from 

 the western locality, none of them preserve any evidence of a longitudinal 

 groove or sinus; the annulating rings are continuous and distinctly oblique, 

 except when the dorsal or ventral side of the specimen is presented to view. 



This species has a wide geographical distribution in the Hamilton group ; 

 and if we recognize the rigid, compressed tubular forms in the fxenesee 

 slate and Portage group, and also in the Marcellus shale, as the same, or only a 

 variety of the same form, with the surface-markings obliterated by maceration, 

 we have also a great vertical range for the species. 



From the* occurrence of these forms with Tentaculites and Styliola, it may 

 be inferred that they have had the same mode of life, and that they more 

 properly belong to the Pteropoda than to the Gasteropoda. 



Formation and localities. In the shales of the Hamilton group near Fulton- 

 ham, Schoharie county ; at Sherburne creek, Chenango county ; at Delphi, 

 Onondaga county ; on the shore of Cayuga lake in several localities ; and at 

 Hamburgh, on the shore of Lake Erie ; having a geographical range of more 

 than 300 miles within the State of New York. It also occurs in limestones of 

 the age of the Hamilton group at the Falls of the Ohio. 



