THE PRE-CAMBRIAN OF WESTERN PATRICIA^ 



E. M. BURWASH 



University of Manitoba, Winnipeg, Canada 



The purpose of this paper is briefly to summarize the results 

 of two seasons' field work in western Patricia. Patricia lies in the 

 extreme northwestern part of the province of Ontario, north of 

 the Winnipeg, EngHsh, and Albany rivers, and their expansions, 

 Lac Seul and Lake St. Joseph. The areas studied by the writer 

 lie in the southwestern part of the district, and in a sense intervene 

 between the classic areas studied by Lawson and others around 

 the Lake of the Woods and Rainy Lake and a number of areas in 

 the province of Manitoba, more recently studied by Bruce, Alcock, 

 Moore, and others. Reconnaisance work had already been done 

 in the Lac Seul region and northward along the Trout Lake, Wen- 

 nasaga, Cat Lake, and other rivers by Bowling, A. W. G. Wilson, 

 Camsell, and others, and the work of E. S. Moore in the region 

 southeast of Lake Winnipeg had extended in a few places across 

 the boundary of Manitoba into Patricia. The writer's work was 

 done under the direction of the Department of Mines of Ontario 

 in the Lac Seul region in 19 19 and along the Ontario-Manitoba 

 boundary from the Winnipeg River northward in 192 1. No great 

 originality or finality is claimed for the results as the work in 

 both cases was confined to narrow strips of country immediately 

 adjacent to the survey-lines or rivers which were traversed, and 

 was not of such a nature as to allow of much areal mapping, 

 which would afford a more complete knowledge of the relation- 

 ships of the various formations than is possible by reconnaisance 

 methods. There has not been time for microscopic study of the 

 rocks in the boundary region, but their general character is evident 

 and in most cases they have been determined already with accuracy 

 by Moore, so that data are now available for at least a tentative 



"■ Read at the Toronto meeting of the American Association for the Advancement 

 of Science. 



393 



