Section IV, 1891. [ 77 ] I^rans. Roy. goc. Canada. 



VII. — 77/e Orthoceratidce of the Trenton limestone of the Winnipeg basin. 



By J. F. "Whiteaves. 



The present paper consists of a critical and systematic list of the Orthoceralidœ at 

 present in the Museum of the Geological Survey of Canada from the formation and region 

 indicated in its title, with descriptions of such species as appear to be new. The whole 

 of the species belonging to the genera included by Dr. Karl Zittel in this family are con- 

 sidered in it, as nearly as possible in the same order as that adopted in the second volume 

 of the "Handbuch der Palœoutologie," but the genera Actinvceras and Sacioceras are here 

 regarded as distinct from Orlhocera!., and Poterioceras from Gomphoceras. 



The term " Trenton limestone " is used in a somewhat comprehensive sense, to include 

 all those highly fossiliferous deposits which immediately and conformably overlie the St. 

 Peter's sandstone and underlie the Hudson River formation. 



"With the exception of two or three examples of a variety of Endoceras annulatum from 

 the Nelson River in Keewatin, the whole of the specimens referred to are from Manitoba, 

 either from the valley of the Red River (at Lower Fort Garry or East Selkirk), the western 

 shore of Lake "Winnipeg, or from some of the numerous islands in that lake. Lower Fort 

 Garry, or Stone Fort as it is sometimes called, is on the west bank of the Red River, 

 seventeen miles N. N. E. of the city of "Winnipeg. The quarry at East Selkirk, from which 

 the fossils from that locality were obtained, is on the east side of the Red River and five 

 miles E. by N. of Lower Fort Garry. 



A few unusually line specimens from East Selkirk were presented to the Museum of 

 the Survey by Mr. A. McCharles in 1884, but most of the remainder were collected by 

 members of the staff during the last ten or eleven years. The exact localities, with the 

 names of the collectors and the date at which the specimens were collected, will be stated 

 under the heading of each species. 



Endoceras annulatum, Hall. Var. 



Plate V, figs. 1 and la. 

 Endoceras annuhilum, Hall. 1847. Pal. St. N. York, vol. i, p. 207, pi. xliv, figs. 1, a, b. 



Between the second and third rapids of the Nelson River, Keewatin, Dr. R. Bell, 

 1879 : a cast of the interior of the septate portion of the shell and two fragments. The 

 most perfect of these specimens, the one figured, differs from the type and only known 

 specimen oIl E. amiulalum, as described and figured by Hall (which is also a septate cast) 

 in the much more oblique disposition of its annular ridges, each of which passes obliquely 

 over three of the septa. In transverse sections, the outlines of both shell and siphuncle 



