156 



F 0 R M A T IONS OF T HE INTERIOR 



Two to two and a half miles above the head of this portage are rapids, where a 

 chain of close-grained quartzose granite, not unlike that of Woodstock, in Maryland, 

 forms the river bed. Above the head of these rapids, gneiss is in place, traversed 

 by veins of granite. Two and a half to three miles higher on the Chippewa, green- 

 stone and hornblende schist protrude, where the rapids again commence. 



Twelve miles above Vermilion Rapids is Brunet's Portage and trading-post. By 

 water, this portage is about three-quarters of a mile, by land one mile. The Chip- 

 pewa is here lined on either side by a dense forest of moderate-sized pines. The 

 rocks are more elevated here than at Vermilion Rapids, and the fall is greater, — 

 about thirty-six feet from the foot to the head of the portage. Hornblende predo- 

 minates in the rocks of this locality. It is seen in some of the beds in distinct 

 crystals of a quarter to half an inch long. Some portions of the rock have the 

 appearance and subcolumnar structure of basalt ; other portions are schistose. At 

 the most turbulent part of the Chippewa, at these Rapids, the rock is more of a 

 bluish pink, quartzose granite, and presents the appearance seen in the annexed 

 vignette. 



H O R N B L, E N 1> I C AND GRANITIC ROCK, BRUNET'S PORTAGE. 



This is one of the most important axis of elevation of the crystalline rocks of 

 the Chippewa, and attracts the attention of the geologist the more, since the struc- 

 ture of the rock partakes of the character of the granitic rocks of Central France. 

 The circuitous waters of the Chippewa here foam around piles of rock, that ob- 

 struct its passage, as it winds its way through the dark pine forest, and lends some 

 variety and interest to the scenery of this part of the Chippewa, which is, for the 

 most part, too same and flat to be otherwise than monotonous and tame. 



Six miles above Brunet's, is another portage, of half a mile. Here also hornblende 

 is the principal constituent of the rocks ; but they are closer grained and more 

 siliceous than at Brunet's, and they are associated with a kind of petrosiliceous, 

 schistose rock, with a very uniform cleavage angle of 26°. The general bearing 

 of the beds is east by north and west by south. 



Above this portage some six miles, and about one mile below the confluence of 



