.344 



THE CANADIAN NATURALIST. 



[Vol. ix. 



Cyrtoceras, sp. 



Two species of this genus occur in the East River collections. 

 One is not distinguishable from the C. suhrectum of Hall (L. 

 Held.) The second is flattened laterally, distinctly bent, the 

 septa one-third centim. distant, in a specimen one centim. in 

 diameter. 



CorniiJites. 



Shells of this species are very abundant in the East River 

 beds. Hall referred the Arisaig specimens to his species G. 

 Jlexuosus ; but from their more slender form named them variety 

 gracilis. At the East River the majority of the specimens are 

 of the Arisaig type, but some more robust. There are however 

 others more slender than any fonnd at Arisaig. Specimens 1.3 

 centimetre in length are only 1 millimetre in breadth at the 

 large end, so that from their slenderness they might be mistaken 

 for Tentacidites, though the annulations are those of Cornulites. 

 But for the apparent connecting forms, these slender specimens 

 might be regarded as types of a distinct species. 



Trilohites. 



There appear to occur at the East River no less than three 

 species of Homalonotus. The most common is H. Dawsoni, Hall, 

 and the others are known to me only by fragments. One has 

 much more numerous annulations on the pygidium than that 

 above named, the other has a nearly smooth pygidium, with about 

 twelve very flat annulations on the axis, and resembling that of 

 H. Vamixemii, Hall, from the Lower Helderberg. The East 

 River collections also add an Acidaspis to the Upper Silurian 

 fauna of Nova Scotia ; but the single specimen found is unfor- 

 tunately too imperfect for description. 



Note. — For information as to the economic geology of this district, 

 I may refer to "Acadian Geology," and to a valuable Keport on the 

 " Mines and Mineral Lands of Nova Scotia," by E. Gilpin, A.M., F.G.S. 

 (Halifax, 1880.) 



