311 



Lituiies convolvans, Hall (non Hisinger) is distinctly included by 

 Hyatt in his genus Barrandeoceras, as stated in the foregoing list of its 

 synonyms. The only difference that can be detected between the two 

 specimens of that species that Hall figures, and the type and only known 

 specimen of B. suhcostulatum is that the former are described and figured 

 as smooth, whereas the surface of the inner whorl of the latter, at least, 

 is distinctly costulate. But, it is only upon well preserved, testiferous 

 specimens that the surface markings are at all clearly shewn, and the two 

 specimens of B. convolvans that Hall figures, are mere casts of the 

 interior of the shell. 



(4.) Bakrandeoceeas vagrans, Billings. (Sp.) 



Plate 40, figs. 1, la, 2 and 2 a. 



Gyroceras (Lituites) vagrans. Billings 1857. Geol. Surv. Canada, Rep. Progr. 



1853-54-55-56, p. 308. 



Original description of Gyroceras (Lituites) vagrans. " Shell elongated, 

 tapering at the rate of nearly two lines to the inch ; laterally compressed, 

 section elliptical, dorso-ventral diameter greater than the lateral, apparent- 

 ly in the proportion of twelve to eight ; about seven inches of the apical 

 extremity of the shell spirally enrolled so as form two whorls not in 

 contact, the interior one of which is one inch in diameter, and the 

 exterior three inches ; septa convex, distant one line and a half at a 

 dorso-ventral diameter of one inch. 



" The specimen exhibits an artificial polished section passing through 

 the central plane of the whorls, showing clearly the construction of the 

 tube to the apex, where it has a diameter of only one line ; some of the 

 septa and almost one-half of the transverse section, but neither the siph- 

 uncle, the character of the surface, nor the length of the produced oral 

 extremity is indicated ; several specimens still lying imbedded in the rock 

 which are known to me, are in my opinion of this species, and if so, then 

 the free portion was gently curved, and in some individuals at least six 

 inches in length, thus giving thirteen inches as the total length. It is 

 scarcely necessary to observe that from the above materials the generic 

 rank of the fragment cannot be determined with the certainty desirable ; 

 the tube is too much curved to come within the definition of Cyrtoceras, 

 the whorls too widely separated for Nautilus or Lituites, and yet, with- 

 out a view of the aperture we cannot say positively that it is a Gyroceras. 



" Formation. — Black River limestone. 



" Localities. — La Petite Chaudifere Rapids, Ottawa River, and in the 

 outcrop of the Black River limestone, near Mile End, St. Lawrence 

 Street, Montreal." 



