1 8 The Ottawa Naturalist. [April 



The writer has seen no specimens of T. Canadensis from Lorette, 

 but if, as seems possible, it there occurs associated with Plectoceras 

 Halliy then the horizon of both of these species at that locality 

 may be that oi the Trenton rather than that of the Black 

 River limestone. 



In Canada it would seem that Trocholites Canadensis is char- 

 acteristic of the Trenton limestone, perhaps of its lower beds, and 

 considerably below the Utica ; T. ammonius of the Utica shale ; 

 and T. planorbiformis of the Hudson River or Lorraine formation, 

 above the Utica. 



Ottawa, March 15th, 1904. 



MOLLUSCA NEW TO THE CANADIAN FAUNA. 



While staying at Oxley, Ontario, in the fall of 1903, Miss 

 Mary E. Walker, of Buffalo, N.Y., made a collection of the mol- 

 lusks found there, which was submitted to me for examination. 

 Among them were two species, which, so far as I have been able 

 to ascertain, have not hitherto been recorded from Canada. 

 I St. — Vallonia parvula, Sterki. 



This is a well marked species, easily distinguished from 

 V. costata by its smaller size, more depressed form and wider um 

 bilicus. Originall)- described from the Western States, it was found 

 by myself several years ago at Put-in-Bay. Its discovery at Oxley 

 extends its range still further north. The occurrence of this 

 species at two localities so near together, and so far away from 

 its normal range, with no known record of its having been found 

 in the intervening region, is a curious fact in distribution, and one 

 not easily accounted for. 



2nd. — PisiDiUM DANiELSi, Sterki. 



This is a new species described by Dr. Sterki in the "Nautilus" 

 for August, 1903, (Vol. xvii, p. 42) from specimens collected in 

 Steuben County, Indiana. Its discovery at Oxley is the first 

 record of its occurrence at any other than the type locality. 



Bryant Walker. 



