LOWER HELDERBERG ROCKS. 34 1 



Fig. 1 a. The lower side of an imperfect specimen, where the umbilicus is iSlled with stony 

 matter. 



Fig. 1 b. The upper side of a larger specimen, the apex of which is imperfect. 



Geological position and locality. In the tentacnlite limestone : Herkimer county. 



Bucaiiia profunda ( n. s ). 



Plate L XVIII. Fio. 1 - 3. 



Shell convolute : volutions exposed, about four, flattened ; inner ones 

 with the width more than twice the depth, becoming more ventricose 

 towards the aperture ; sides obtusely angular, the casts obscurely ca- 

 rinated upon the back : aperture very abruptly and widely expanded. 



This species is common in the Upper Pentamerus limestone; occurring in the 

 condition of the specimen fig. 2, more rarely as fig. 3, and a single specimen has 

 been obtained where the impression of the widely expanded aperture is preserved 

 upon the surface of the stone. The true extent of this part of the shell cannot be 

 ascertained, since the margin is not defined. 



This species may be compared with Bellerophon dilatatus (Sowerby), Murchison, 

 Silurian System, Part ii, pa. 627, pi. 12, f 23 & 24 ( Siluria, pi. 25, f.5 & 6); 

 PoRTLocK, Geological Report of Londonderry, etc., pa. 398, pi. 29, f. 1 : also with 

 Bellerophon macrostomum, Rcemer, Rheinische Uebergansgebirge, pa. 80, pi. 2, f 6 

 a, b; but our species differs from either of these. 



Fig. 1 a. Dorsal view of a cast, in which the expanded peristome is shown upon iuv Sitrface 



of the stone. 

 Fig. 1 6. Lateral view of the same. The representation of the volutions is incorrect. 

 Fig. 2 a. A small specimen in which the expanded portion is broken off. 

 Fig. 2 b. Lateral view of the same. 



Fig. 3 a. A specimen having a part of the outer volution broken off. 

 Fig. 3 6. The umbilicus, showing three volutions. 

 Fig. 3 c. Dorsal view of the same, showing an obscure carination. 



Geological position and locality. In the upper pentamerus limestone : Schoharie 

 and Carlisle, Schoharie county. 



