91 



Pleurotomaria Postumia. (N. sp.) 



Description. — Discoidal ; spire varying from gently convex to flat, or 

 even a little concave ; whorls five or six, very slender, very slightly 

 convex on the upper side; outer edge very acute and a little turned 

 upwards ; outer and lower side gently convex and forming an angle of 

 from 60° to 80° with the upper side ; lower side rounded, and sometimes 

 obtusely carinated along the middle ; umbilicus very wide, extending to 

 the apex. Surface unknown. 



Width of a specimen of six whorls 18 lines; width of last whorl 3 

 lines ; depth about the same. 



Locality and Formation. — Point Levis ; in limestone No. 2. Also, at 

 Phillipsburgh in limestone of the same age. Quebec group. 

 Collectors. — Sir W. E. Logan, R. Bell, Dr. J. B. Farnsworth. 



CEPHALOPODA. 

 Orthoceras Autoltcus. (N. sp.) 



Description. — Section circular, tapering at the rate of about 1| lines to 

 the inch. Septa moderately concave, from eight to ten in one inch. 

 Siphuncle about one line in diameter, marginal, m contact with the shell. 



This species is common, but always found in fragments. It appears to 

 be about 1 foot in length, and 1^ inches in diameter at the larger extremity. 

 It is slightly curved, as are most of the Orthoceratites in the Chazy and 

 Calciferous formations. The siphuncle is small and lateral, in contact with 

 the shell on the side of the convex curvature. The chamber of habitation 

 seems to be deep, for in a small specimen only 7 lines in diameter it is 1 

 inch in length, and, besides this, a portion seems to be broken away. The 

 larger extremity exhibits a number of broad, shallow annulations, which 

 cross the shell obhquely, and in some specimens seem to be interrupted on 

 the side of the convex curve. Surface markings of shell unkno\>Ti. 



Locality and Formation. — Point L^vis ; in limestone No. 2. Quebec 

 group. 



Collectors. — Sir W. E. Logan, J. Richardson, R. Bell. 



