RECENT STUDIES IN THE GRENVILLE SERIES OF 

 EASTERN NORTH AMERICA^ 



FRANK D. ADAMS 

 McGill University, Montreal. 



In a paper which has recently appeared^ a summary of the chief 

 results of a geological study of a large area on the margin of the 

 Laurentian protaxis in eastern Ontario, by Dr. Barlow and the writer, 

 has been presented. The area in question, whose study has just 

 been completed, is one of the largest areas of the protaxis which has 

 hitherto been examined, comprising 4,200 square miles, and the study 

 has furthermore been carried out in much greater detail than in the 

 case of areas formerly examined in Canada, the field work extend- 

 ing over a period of eight years. In a second paper^ now in press a 

 more detailed account of the great development of nepheline and 

 corundum-bearing syenites found in the area is given. 



The area lies near the border of the Laurentian protaxis, north of 

 Lake Ontario and east of Lake Huron, and one of the most con- 

 spicuous features of its geology is the great development in it of Logan's 

 Grenville series. It is proposed in the present paper to present 

 certain new facts which have been discovered concerning this series 

 in the area in question, as well as certain general considerations relative 

 to this, which is one of the most extensive and important series of 

 pre-Cambrian Age -in North America. A complete description of 

 the area will appear in the form of a report to be issued by the 

 Geological Survey of Canada during the present year. 



In The Geology of Canada,"^ published in 1863, which contains a 

 statement of the results of the work of the Canadian Survey up 

 to that date, Logan commences the chapter dealing with these rocks 

 as follows: 



1 Communicated by permission of the Director of the Geological Survey of Canada, 



2 Frank D. Adams, "On the Structure and Relations of the Laurentian System 

 in Eastern Canada," Quarterly Journal of the Geological Society, May, 1908, p. 127. 



3 "On the Nepheline and Alkali Syenites of Eastern Ontario," Transactions of 

 the Royal Society of Canada, 1908. 



4 P. 22. 



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