26 
MUSEUM BULLETIN NO. 8. 
greywacke, limestone, and laminated greywacke (slate con- 
glomerate group) and a thick, feldspathic quartzite. This 
succession, however, was shown in 1913 to be the same thing as 
the Cobalt series of Cobalt and adjoining districts. Also, the 
boulder conglomerate member is the Ramsay Lake conglomerate 
of Professor Coleman^. Upper Huronian and Cobalt are, there- 
fore, just different names for a single series and Ramsay Lake 
conglomerate a name for one member of this series. 
The equivalence of these names makes the series they 
designate a common plane of reference for the correlation of the 
Pre-Cambrian formation in the Original Huronian, Sudbury, 
and Cobalt districts. Column I in the accompanying table 
gives the succession for the Original Huronian district as rep- 
resented by Bruce and Blind River areas. The names used are 
those given by Logan, Winchell, and others, supplemented by 
some new ones. Columns 1 1 and III, for Sudbury and Cobalt 
districts, are essentially the classifications of Coleman and Miller, 
respectively. Column IV is a composite of the other three, 
applicable to Timiskaming region. 
Exception may, perhaps, be taken to the use in column IV 
of the names Cobalt series and Bruce series instead of Upper 
Huronian and Lower Huronian. The latter names are, indeed, 
preferable on the ground of priority, but they convey too precise 
significance for the present developmental state of Pre-Cambrian 
classification in Timiskaming region. There is no certainty that 
the upper of these two series forms the natural termination of the 
Huronian system, since the nature of its relations to younger 
sedimentary series in this region remains undetermined. So, 
why call it Upper Huronian? Moreover, the use of Upper 
Huronian and Lower Huronian might convey the incorrect im- 
pression that these series in Timiskaming region are correlated 
with series of the same name in the Lake Superior region. Ac- 
cordingly, the only widely current equivalent for Upper Huronian, 
that is, Cobalt series, has been adopted. No such equivalent 
already exists for Lower Huronian so, rather than accept that 
compromising term, and for consistency in the use of local 
names, Bruce series is suggested as a substitute. 
^ The Nickel Industry: Publication No. 170, Mines Branch, Department 
of Mines, Canada, page 9. i _ ' m 
