Hume — Paleozoic Outlier of Lake Timiskaming. 293 



Aet. XXI. — The Stratigraphy and Geologic Relations of 

 the Paleozoic Outlier of Lake Timiskaming; 1 by Geoege 

 S. Hume. 



Introduction. 



The Paleozoic outlier of the Lake Timiskaming district 

 is situated just a few miles northeast of the mining town 

 of Cobalt, Ontario, and about 130 miles north of the east- 

 ern part of the north shore of Lake Huron. The area, 

 which includes about 250 square miles, is restricted to a 

 number of islands at the northern end of Lake Timiskam- 

 ing and a strip of country not over 9 miles wide extending 

 as far north as Englehart. This outlier is completely sur- 

 rounded regionally by more elevated rocks of Precam- 

 brian age. 



Previous work. — Paleozoic rocks were first reported 

 from the Lake Timiskaming district in 1845. The first 

 contribution of any importance on the geology was made 

 by R. Bell in 1894 in a paper entitled ' ' The pre-Paleozoic 

 decay of the crystalline rocks north of Lake Huron. ' ' In 

 it the conclusion is reached that the Paleozoic rocks are 

 later in origin than the depression which now forms Lake 

 Timiskaming. This view was also held by Barlow ( 1897 ) , 

 who made a more extensive study of the district, the re- 

 port of which was published in 1897. The Paleozoic rocks 

 were ascribed to the Clinton and Niagaran formations, 

 and from loose fragments Trenton fossils were also ob- 

 tained. It was concluded that Trenton was present 

 though concealed. 



The regional relationships of the district, with especial 

 reference to the Precambrian, have been studied particu- 

 larly by W. G. Miller (1913) on the western or Ontario 

 side of the lake, and by M. E. "Wilson (1918) on the east- 

 ern or Quebec side. They have shown that the Paleozoic 

 sediments are older than the formation of the Timiskam- 

 ing trench, which was also studied somewhat by both Bell 

 and Barlow previously. 



In a short, reconnaissance trip M. Y. Williams (1915) 

 found Ordovician sediments of Trenton age on the west- 

 ern side of Lake Timiskaming, and for the first time 

 proved the existence of a fault along the straight western 

 shore of the lake. Faulting had previously been sus- 



1 Published by permission of the Director of the Geological Survey of 

 Canada. 



