GEOLOGICAL OBSERVATION.--. 31 D 



fine-grained iron-pyrites and specks of yellow sulpkuret, in a yellowish 

 quartzose gangue. Here the iron-pyrites constitutes as much as 

 fifteen or twenty per cent, of the rock, while along the whole of the 

 distance above described, about one and a-quarter miles, it is never 

 absent, though occurring in small quantities. At the last mentioned 

 place is the depression before described. As before stated, it is filled 

 with drift, and no rock is seen in it ; but from the quantities of iron 

 and copper-pyrites met with in the rock on both sides of it, it is quite 

 possible that under the drift a valuable deposit of copper ore may exist. 



"Iron. — About balf-a-mile south-west of the tirst mentioned copper j rim- 

 ore, and near the lake shore, there is a deposit of magnetic iron ore in 

 chlorite slate; its breadth is fifty feet, and it is seen on its strike, 

 which is S. 65° W., and K 65° E., about 200 paces. The ore occurs 

 in crystalline lumps and grains throughout the rock. The whole 

 iifty feet would probably yield an average of from fifteen to twenty 

 per cent, of iron. 



"Ochre. — The only place this was observed was in the north-east odiro. 

 part of Paint Mountain, where a small deposit was met with about 

 halfway up the mountain, which probably derives its name from the 

 presence of this ochre or paint." 



Cambrian. 



The limestones found on Lakes Mistassini and Mistassinis, owing to 

 the absence of any fossil remains, have been referred to this horizon on 

 account of their lithological resemblance to Cambrian rocks of the east 

 side of James Bay. 



These rocks form the basin of the two lakes, and extend but little , 



Area. 



beyond their shore line. The south-west boundary is at the end of 

 Abatigoush Bay, where they succeed the Huronian rocks seen on Lake 

 Wakiniche, the contact of the formations being concealed by drift. 



Following the western limit, we next find the limestones in contact 

 with, and lying unconformably on, the Laurentian gneiss, on Poni- 

 chuan Bay, at the place where the bay narrows. The boundary then 

 follows along the north-west shore of the lake to the north-east end, 

 and I think continues in the same course to a low range of hills, 

 which lies about ten miles beyond the end of the lake. 



Sweeping eastward along the base of these hills, the rocks extend 

 beyond the south-west side of Lake Mistassinis, and are seen to occupy 

 the whole of that shore. 



Mr. Bignell describes the limestones as occurring several miles on 

 the Temiscamie Biver, from its inlet to Lake Mistassinis. 



