APPENDIX. 325 



exbibit an exterior of glistening cells or orifices: it may be possi- 

 ble that they have been produced by fusion ; but I think not. 

 The smooth cells appear like grains of sand hurled by the winds 

 over these bleak dunes. I have brought from that locality a 

 single specimen of pitchstone, perfectly resinous, bleak and 

 shining. 



La Pointe Chegoimegon. — A sketch of these islands, as given 

 in the Narrative, denotes that their number is greatly underrated, 

 and will serve to show the configuration of a very marked part 

 of the Superior coast. It must, hereafter, become one of the 

 principal harbors and anchoring-ground for vessels of the lake. 



Valley of the St. Louis River. — The St. Louis River takes 

 its rise on the southern side of the Hauteur des Terres, being the 

 same formation of the drift and erratic block stratum which 

 gives origin, at a more westerly point, to the Mississippi. Its 

 tributaries lie northwest of the Rainy Lakes. Vermilion Lake, 

 a well-known point of Indian trade, is a tributary to its volume, 

 which is large, and its outlet rushes with a great impetus to the 

 lake. At what height its sources lie above Lake Superior, we 

 can only conjecture. It was estimated to have a fall of two hun- 

 dred and nine feet to the head of the Portage aux Coteaux, and 

 may have a similar rise above. 



By far its most distinguishing feature is its passage at the 

 Grand Portage through the Cabotian Mountains. We entered it 

 at Fond du Lac and pursued up its channel through alluvial 

 grounds, in which it winds with a deep channel about nineteen 

 or tv/enty miles to the foot of its first rapids. This point was 

 found one mile above the station of the American Fur Company's 

 trading-house. Here we encountered the first rock stratum, in 

 the shape of our old geological acquaintance, the old red sand- 

 stone of Lake Superior. It was succeeded in the first sixteen 

 miles, in the course of which the river is estimated to fall two 

 hundred feet — most of it in the first twenty-nine miles — by trap, 

 argillite, and grauwacke. Through these barriers the water forces 

 its way, producing a series of rapids and falls which the observer 

 often beholds with amazement. The river is continually in a 

 foam for nine miles, and the wonder is that such a furious and 

 heavy volume of water should not have prostrated everything be- 

 fore it. The sandstone, grauwacke, and the argillite, the latter 



