Sectiox I\', 1921 [25] Trans. R.S.C 



Mesozoic Clays and Sands in Northern Ontario 



By Joseph Keele^ 



Presented by R. A. A. Johnston, F.R.S.C. 



(Read May Meeting, 1921) 



Introduction 



In the autumn of 1918 several samples of clay were sent for 

 examination to the clay testing laboratory of the Mines Branch, 

 Department of Mines of Canada. These samples were collected on 

 the bank of Mattagami river by Mr. C. M. McCarthy of Elk Lake 

 from outcrops just north of the lower end of Long Portage. 



An examination of the samples convinced the writer that they 

 represented highly refractory clays of rare occurrence in Canada and 

 were undoubtedly of pre-Glacial age. 



Small samples from other high grade clays known to occur on 

 Missinaibi river were procured from the owners, and these likewise 

 proved to be pre-Glacial clays similar to those on Mattagami river, 

 40 miles distant. 



It appeared, then, to the writer that there were remnants of a 

 group of sediments in this region which were probably of Tertiary 

 age, or perhaps older, and that it was advisable to visit the localities 

 and examine the deposits. 



Two short journeys were made in 1919 and 1920, and evidence 

 was secured which proved not only that the clays were pre-Glacial 

 but also that they were probably of Lower Cretaceous age. 



The clays and sands on Missinaibi river, where the most con- 

 spicuous outcrops occur, attracted the attention of several previous 

 explorers, who attributed their origin to glacial transport and deposi- 

 tion, some calling them inter-Glacial. 



Most of the explorers, however, were chiefly concerned with 

 metallic minerals, and soft deposits like these were not very closely 

 scrutinized. Furthermore, it was inconceivable to them that such 

 soft deposits could have survived the destructive effects of glaciation. 



The composition and physical characters of these materials 

 show that they have no relation whatever to glacial products. Sedi- 

 ments like these could not have been laid down in any region sub- 

 ^ Published by the permission of the Deputy Minister of Mines. 



