PRE-CAMBRIAN OF NORTHERN ONTARIO AND QUEBEC 307 



bedded conglomerates and greywackes folded into a tight syncline 

 with vertical or very steep limbs. Miller correlates this series 

 with a similar closely folded conglomerate near Cobalt, previously 

 called Timiskaming series. They recognize that it is much older 

 than the Cobalt series, since the latter is found in Grenfell Town- 

 ship, to the west of Teck, lying flat within a quarter of a mile of 

 the folded Timiskaming. The Cobalt series is regarded as probably 

 Upper Huronian or Animikean in age, and the Timiskaming as 

 Lower Huronian.^ 



The sediments continue without interruption (Fig. 3) from 

 Gauthier Township eastward into McVittie and McGarry town- 

 ships (Larder Lake district), where they are described by Brock 

 and Bowen (1907) and later by M. E. Wilson (1908-9) as con- 

 sisting of slates, carbonate rocks, and greywackes interbedded with 

 basic altered lavas and therefore as of Keewatin age. Some 

 steeply dipping conglomerates found to the north and south of the 

 slates and other rocks are mapped as isolated patches of Cobalt 

 conglomerate deformed by local disturbance. 



Some four miles to the east of Larder Lake there outcrops the 

 sedimentary series named the Pontiac schigts by M. E. Wilson. 

 These are separated from the Larder Lake sediments by a band 

 of fiat-lying sediments belonging to the Cobalt series (Fig. 3). The 

 Pontiac series has been described by M. E. Wilson and J. A. Ban- 

 croft as a series of interbedded conglomerate and greywacke, 

 folded into a vertical position, overlying the Keewatin unconform- 

 ably, and underlying the Cobalt series with great unconformity. 

 The similarity of the descriptions of the Pontiac conglomerates 

 and greywackes and the corresponding members of the Timiskam- 

 ing series of Kirkland Lake is pronounced. 



The geological descriptions which have been briefly summarized 

 appeared to the writer to indicate either that some error had been 

 made in the study of one of the areas, or that there was more there 

 than any of the geologists had recognized. Under the latter 

 hypothesis it was conceived that there might be two ancient 

 sedimentary series in the district, one of which was the better 

 developed in each area, and that a different one had been 



^Oni. Bur. Mines, RepL No. 22, pp. 123-27, 1913. 



