﻿240 



Cincinnati Society of Natural History. 



8. O. annulatum, Sowerby. 1818. 



Mineral Conchology. Tab. 133. 



Hall, Pal. of N. Y. II, p. 96, PI. 29, fig. 3. 



Hall, 1 8th Regents report. Printed in 20th Report Regents 

 N. Y. p. 351, PI. 20, figs 4, 5, 6. 



Hall & Whitfield, Pal. of Ohio II, p. 147, PI. 9, fig. 1. 



White, C. A. Eleventh Rept. State Geol. Ind., (1881), p. 358, PI. 

 38, fig. 1. 



O. undulatum, Hisinger. (Hall.) Pal. N. Y, II, p. 293. PI. 

 64, figs. 1a to/, and PI. 65, fig. 3. 



Shell cylindrical, very gradually tapering : strongly cumulated: annu- 

 lations sharply elevated, rounded on top, with deep, concave depressions 

 between them ; septa deeply concave ; siphuncle sub-central ; surface of shell 

 with concentric lines of growth, and more or less distinct longitudinal 

 ridges. 



Locality: Versailles, Ind., Westboro, Ohio. 



This species is easily recognized by the strong annulations and con- 

 cave septa. The longitudinal ridges are often obscure. It has been 

 found in the Niagara and Clinton Groups of New York, Ohio and Indiana, 

 and is identical with English and Swedish specimens. 



9. O. turbidum, Hall & Whitfield. 1875. 



Ohio Geol. : Pal. II, 100, PI. 3, fig. 1. 



Shell moderate size, gradually tapering; septa not close, slightly con- 

 cave ; siphuncle unknown ; surface marked by low, rounded, longitudinal 

 ridges, four or five in space of one-half inch. 



Locality : Cincinnati. 



The distant septa serve chiefly to characterize this species, and taken in 

 connection with the longitudinal lines will serve to distinguish it. The 

 figure shows the septa to be irregular, as if weatherworn. 



10. O. hindei, James. 1878. 



(Palaeontologist, p. 1.) 

 (PI. 4, figs. 4 a to d.) 



Shell small, semi-cylindrical, gradually tapering, sometimes to a point ; 

 septa arched, oblique, three-quarters of a line to a line wide; section 

 semi-cylindrical; siphuncle cylindrical : Length one-half to three inches. 



Locality : Cincinnati. 



This species is remarkable in being semi-cylindrical; in all the speci- 

 mens the under side seems to be wanting, so that the section is a half 

 circle instead of a whole one as in the rest of the species. Some of the 



