PLATE XL. 



(The specimens figured on this plate are from the Black 

 River limestone at La Petite Chaudiere Rapids, on 

 the Ottawa River, near Ottawa city.) 



Barrandeoceras VAGRANS (page 311). 



Figure 1. Inner surface of the type of this species, which has been rubbed down and 

 poliahed in such a way as to exhibit an " artificial polished section pass- 

 ing through the central plane of the whorls." 

 II 1 a. Outline of a partially restored transverse section of part of the same speci- 

 men. 



Figure 2. Side view of an imperfect cast of the interior of the chambered jjortion of 

 the shell of a specimen that is probably referable to this species, shewing 

 many of the sutural lines on its convex surface. 

 II 2 a. Portion of the vender of the same, in outline, shewing three of the ventral 

 saddles. 



Cyrtoceras sinuattjm (page 312). 



Figure 3. Side view of the exterior of a fragment of a specimen that is probably 

 referable to this species, and that shews the surface markings of the tesc. 

 (This fragment was figured inadvertently on this plate, when the writer 

 was under the impression that the former was a very imperfect specimen 

 of Barrandeoceras vagrans.) 

 IP 3«, Inner surface of the same fragment, which has been broken longitudinally 

 and weathered in such a way as to shew the edges of several of the septa, 

 and the shape and relative position of the siphuncle. 



