CHURCHILL AND NELSON RIVERS. 13 C 



Lower Chairi-of-Eocks (or Islands) Rapid, with a descent of only about 

 two feet, occurs one mile further down. 



Between the Grand Rapid and the western part of Split Lake the Gneiss, 

 gneiss is partly reddish and partly grey and hornblendic. The strike 

 varies in different places from S. 60° to S. 80° W. It is cut by a num- 



Dykes. 



ber of dykes of dark-coloured diorite, some of which, just below the 

 junction of the Grass River, are very large. Their run has a general 

 north-and-south tendency. On the north side of Split Lake, opposite 

 the two inlets of the Nelson, the gneiss is cut by numerous dykes of 

 all sizes and running in many directions. Below Chain-of-Rocks 

 Rapid, on the north-west side of the river, dark grey quartzite and 

 hornblendic schist occur, and also a dark green serpen tinous-looking ,c 1S s 

 rock with a somewhat schistose structure. The Burntwood River, a r^V™ 

 large stream, with turbid water like that of the Nelson, enters the 

 western extremity of Split Lake. On each side of the mouth of this 

 river, the rocks consist of quartzose, fclsitic and hornblendic slates, run- Schlsts - 

 ni ng west-south-west, much cut up by trap dykes. At the Island of the 

 Dead, in the entrance of the river, hornblendic schist is interstratified 

 with ribboned quartzite, striking east and west. The rocks on some 

 islands about a mile north-east of the western or principal inlet 

 of the Nelson River, consist of dark bluish-green hornblende and mica 

 schist, interstratified with ribboned gneissic bands and with irregular 

 layers of softer, light green schist, all much contorted. The rocks of 

 the point between the Nelson and Burntwood rivers, and the islands 

 for two miles to the north-west of it, may be considered as Huronian, Huronian- 

 but beyond this, in the same direction, they pass into gneiss, consisting 

 of thin hornblendic and micaceous layers, alternating with others of 

 quartz. 



Split Lake runs east-north-east, and is about twenty-five miles long Split Lake, 

 by two or three wide. The rocks along its northern shore consist of 

 gneiss, which is generally of a hornblendic character, interstratified 

 with quartzose layers. Towards the west end the strike is about east 

 and west, but elsewhere it is much disturbed. Besides the rocks of 

 Huronian character just described as occurring at this extremity of the 

 lake, a green hornblende rock, which was met with on an island near 

 the east end, may be of the same age. "What appears to be another 

 limited area of Huronian rocks in this part of the country, is met with Huroniaii on 

 on the south side of the Grass River where it joins the Nelson. Here, Grass Rlver- 

 at about half a mile west of the Grand Rapid portage, there is a rib- 

 boned, slaty, hornblendic rock, together with a coarse variety, and a 

 dark gray quartzite, dipping S. 20° W. < 60°. These are cut by a 

 great dioritic dyke, running about north and south. Siliceous and 



