﻿480 Canadian Record of Science. 



Problems in Quebec Geology. 



Read at the meeting of the British Association, Toronto, August, 1897. 

 By R. W. Ells, LL.D., F.R.S.C. 



Probably no questions in Canadian geology are of 

 greater interest, or have been more widely discussed, than 

 those connected with the complicated structure of some 

 of the rock formations, found in the Province of Quebec, 

 which are located on both sides of the St. Lawrence river. 

 That on the north of the river relates to the vexed 

 question of the origin and structure of the oldest 

 crystallines or the rocks of the Laurentian system ; while 

 to the east of the St. Lawrence the relations of the 

 several divisions of the fossiliferous sediments to each 

 other, and to the crystalline schists of the Sutton 

 Mountain range, as well as the structure of the latter 

 group, have long been a subject for study to those 

 interested in the interpretation of one of the most 

 puzzling problems with which the Canadian Survey has 

 had to deal. 



The history of the attempt to work out the structure of 

 the Archaean or Laurentian rocks north of the St. 

 Lawrence dates back nearly fifty years. After several 

 seasons devoted, in part, to the general examination 

 of the rock masses along the course of the St. Lawrence, 

 Sir William Logan, in 1853, began the detailed study 

 of 'an area north of the Eiver Ottawa, in the county 

 of Argenteuil, which might be ta'ken as the foundation of 

 all subsequent work on these oldest rocks in Canada. 

 The complicated arrangement of the various gneisses, 

 limestones and quartzites, with granite, greenstone and 

 other igneous masses, which is there presented has 

 furnished, for half a century, a problem of undiminished 

 interest to the geologist. 



In the earliest days of their study a working hypothesis 

 was adopted which held that the greater portions of the 



