THE OTTAWA fiATURALIST. 



Vol. XVI. OTTAWA, OCTOBER, 1902. No. 7. 



ON THE GENUS TRIMERELLA, WITH DESCRIPTIONS 



OF TWO SUPPOSED NEW SPECIES OF THAT 



GENUS FROM THE SILURIAN ROCKS 



OF KEEWATIN. 



'(With two plates.) 



By J. F. Whiteaves.* 



In the summer season of 1901, Mr, D. B. Dowling, of the 

 Geological Survey, made an interesting and somewhat large col- 

 lection of fossils from limestone exposures at five different locali- 

 ties on the Equan River, and at Sutton Lake. The Equan River, 

 it may be mentioned, is the first river north of the Attawapishkat, 

 with which it flows, almost parallel, into the west side of James 

 Bay; and Sutton Lake is the source of Trout River, which empties 

 into the southern portion of Hudson Bay, as does also the Severn 

 River. These fossils have not yet been exhaustively studied, but 

 enough is known about them to show that the rocks from which 

 they were collected belong to the Silurian, as distinguished from 

 the Cambro-Silurian or Ordovician system, and that they are 

 probably of about the same age as the Guelph formation and 

 Niagara limestone of Ontario. They show, moreover, that the 

 limestones and dolomites of the Attawapishkat River and of the 

 Fawn Branch of the Severn River, that were formerly thought to 

 be Devonian on the evidence of a few fossils collected by Dr. R. 

 Bell and Mr. A. P. Low in 1886, belong also to the Silurian 

 system, and that they are of precisely the same age geologically 

 as the Equan River limestones. They include some species that 

 are found also in the Silurian limestones, etc., of Port Daniel and 



*Communicated by permission of the Acting- Director of the Geologfica 

 Survey of Canada. 



