THE COBALT SERIES; ITS CHARACTER AND ORIGIN! 
MORLEY E. WILSON 
Canadian Geological Survey, Ottawa 
INTRODUCTION 
In that part of northern Ontario and Quebec of which Lake 
Timiskaming is the geographical center, a series of pre-Cambrian 
clastic sediments occur which are of peculiar interest to the geolo- 
gist, not only because they form the country rock of the larger part 
of the rich silver-bearing veins of the Cobalt mining camp, but 
because, as is shown in the following pages, their character is such 
as to indicate that they are entirely of terrestrial origin and have 
been deposited in part from continental glaciers. If the fore- 
going conclusion be correct, then another glacial period more 
ancient than any of those yet described in other parts of the world 
is added to our knowledge of the geological history of the earth, 
and positive evidence is afforded as to the remarkable uniformity 
of geological processes even in pre-Cambrian times. 
In order to reach a logical conclusion as to the manner in which 
any series of rocks has been deposited, full information as to the 
character and geological relationship of the series as a whole and of 
all its members is necessary. The following discussion is therefore 
divided into two parts, in the first of which the geological relations 
and lithological character of the Cobalt series is described, and in the 
second, an application is made of those criteria from which the mode 
of origin of the various members of the series may be inferred. 
GEOLOGICAL RELATIONS AND CHARACTER OF THE COBALT 
SERIES 
GENERAL GEOLOGY OF THE TIMISKAMING REGION 
Geologically this region belongs to the great Canadian shield 
of pre-Cambrian rocks which occupies the greater part of north- 
t Published by permission of the Director of the Geological Survey branch of 
the Department of Mines, Canada. 
Part of a thesis contributed to the Department of Geology of Yale University 
in partial fulfilment of the requirements for the degree of Doctor of Philosophy. 
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