﻿2o2 Canadian Record of Science. 



Trenton formation, were the oldest members of what was 

 known as the Quebec Group. 



This view was subsequently opposed by Dr. Sterry Hunt, 

 and also by Dr. Selwyn, soon after his appointment to the 

 directorship of the CJeological Survey, who advanced the 

 theory that the Trenton is the most recent instead of the 

 oldest formation here found, and that the other members 

 of this series are older than the Quebec Group, and are of 

 Huronian age. 



In support of his earlier views, Logan, after having 

 retired from the Survey, spent several seasons in a 

 re-examination of the disputed ground, studying chiefly 

 the townships of Melbourne, Cleveland and Shipton, 

 which he considered to give the key to the structure of 

 the Quebec Group. He had these townships topographi- 

 cally surveyed at his own expense, and proceeded to 

 prepare a geological map of the district in considerable 

 detail. Having all but completed the work which he con- 

 sidered necessary for the vindication of his position, he 

 died without making public any results of his work, nor 

 have they since been published. Entirely apart from any 

 controversial interest, it is much to be regretted that the 

 result of what was, perhaps, the most complete geological 

 investigation that has ever been made of any area of equal 

 complexity, size and importance in Canada, should not 

 have been made known. 



The task of elucidating this tangled question was, how- 

 ever, reserved for Dr. Ells, whose w^ork appears in the 

 reports of 1886 and 1896. Beginning at the Vermont 

 boundary line, he traced the Sutton mountain ridge in a 

 north-easterly direction, and by a very extensive series of 

 observations arrived at conclusions essentially similar to 

 those of Dr. Selwyn, viz. ; that the chief rocks of this 

 range are of Huronian age. 



The intrusive rocks in this sheet, exclusive of the Lau- 

 rentian, comprise the line of volcanic mountains which 



