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June 7, 1915 
Canada 
Geological Survey 
Museum Bulletin No. 17. 
GEOLOGICAL SERIES, No. 27. 
The Ordovician Rocks of Lake Timiskaming. 
By M. Y. Williams. 
INTRODUCTION. 
The isolated Silurian rocks of Lake Timiskaming have long 
been of interest to the geologist. Sir Wm. Logan described them 
first in 1845 and again in the Geology of Canada, 1863, (page 335.) 
In 1897, Dr. A. E. Barlow described these rocks in the annual 
report of the Geological Survey of Canada. Logan, in his 
description, states, “at Lake Temiscamang, there are found lying 
on the Niagara limestone, loose angular fragments of dolomite, 
resembling that of the Birdseye and Black River formation of 
Lacloche and Lake Nipissing, and holding Strophomena alternata, 
species of Maclurea like M. magna, and M. Atlantica , Orthoceras 
anceps , and 0. proteiforme. The source of these fragments 
has not yet been ascertained.” Barlow quotes from Logan and 
says further: 1 “The lake is here over 200 feet in depth and it 
is just possible that below the Niagara limestone and concealed 
beneath the waters of the lake there exists an area of Cambro- 
Silurian rocks.” Until last autumn this was the status of our 
knowledge of the Ordovician rocks of this region. 
1 Geol. Surv., Canada, Vol. X, 1897, p. 124 I. 
