GASTEROPODA. gg 



be determined. The inner volutions are moderately elevated above the plane 

 of the outer one, differing in this respect from E. inops, while the abrupt 

 depression of the umbilicus from the inner margin of the volution is a 

 distinctive feature. The spire is a little more elevated than that of E. Hecale, 

 and the base of the outer volution is rounded and not flattened as in that 

 species. It differs very little from entire specimens of E. Eboracensis, except 

 in the contact of its volutions. 



Formation and locality. In the shales of the Hamilton group, at West Bloom- 

 field, Ontario county, N. Y. 



Ecomphalus (Straparollus) Hecale. 



PLATE XVI, FIGS. 10-14. 



nphalus Hecale, Hall. Illustrations of Devonian Fossils: Gasteropoda, pi. 16, figs. 10-14. 1876. 

 Com[>ai-e Kiuimphaliu depressus,* Hall (non Gold.). Geol. N. Y. Surv. Fourth Geolog-. Dist., p. 291. 1843. 



Shell discoid, spire depressed. Volutions about three or four, contiguous, 

 rounded, the inner ones slightly elevated above the plane of the outer one, 

 gradually enlarging from the apex, very slightly expanding at the aper- 

 ture and flattened on the lower side. Umbilicus broad, descending abruptly 

 from the inner basal margin of the volution, which is rounded on that side. 



Surface concentrically striated — the striae often crowded in fascicles or ridges 

 towards the aperture. 



This is probably the same species described in the Report of the Fourth 

 Geological District as Euomphalus depressus (not E. depressus of Goldfuss).* 

 Comparatively few specimens of this form have occurred among large collec- 

 tions of other fossils from the same formation, and these are principally casts 

 of the interior, which sometimes preserve marks of the external striae, and 

 ridges left by the stronger fascicles, near the aperture. In form and propor- 

 tions it resembles E. laxus of the Hamilton group, from which it differs in 

 having the volutions in contact. 



Formation and localities. In the Chemung group at Rockville, Allegany 

 county, near Ithaca and Elmira, N. Y., and at Meadville, Penna. 



* The original of E. depressus, Hall, is not now accessible to the author for comparison. 



