﻿218 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 9, 



low, except on the N.E., and its shores usually marshes or sunken 

 mounds of rock. 



But quartzy sand, with and without primitive pebbles and banks 

 of gravel, or beaches, were not entirely wanting ; the sand is coarse 

 and gritty, and reddish yellow, as in most of the small lakes between 

 this and Lake Superior. 



Boulders are general and very large, some weighing tons, mode- 

 rately rounded, and often angular. Those of the Lake of the Woods 

 are sometimes, but not often, seen here ; but these mostly belong to 

 the lake itself, and consist of grey gneiss (with staurotide), white 

 granite, trap, greenstone-slate, greenstone-conglomerate (the nodules 

 being primitive), very much mica-slate, large-grained syenite, and 

 hornblende-rock ; most of these rocks occur in the fixed state in the 

 lake, and especially at the north-east end. 



These deposits hang upon the lake-shores without any display of 

 stratification, and seem to belong to the present system of things. 



Lake Lacroix. — I merely crossed over this lake — the next large 

 body of water. It is full of islands, and did not exhibit on its surface 

 much detritus ; but it is fertile in parts. Most of the larger erratics 

 are angular and often many feet long and broad. They are of the 

 lake and may be called home-erratics ; — consisting of slabs of mica- 

 slate, greenstone-slate, and various granitoids. 



From Lake Lacroix to Lake Superior, a distance of 1 77 miles, my 

 opportunities for observation were very scanty. I was hurried along 

 narrow watercourses, marshes of wild rice, through shallow lakes, or 

 extensive sheets of water bounded by basalt slopes and precipices. I 

 noticed, however, that almost universally all the obstructions to the 

 water-way, such as narrows, shallows, and cascades, were encumbered 

 with boulders and gravel. 



Lakes La Croche and Keseganaga. — In Lake La Croche there are 

 banks of brown sand and clay, with large primitive blocks, sometimes 

 so white and large as to look like a group of white Canadian houses. 



Seven miles from the Upper Portage of this lake, there is a still- 

 water narrow, only thirteen yards wide, so choked up with angular 

 boulders, probably native, that our canoe could barely work through 

 them. Of this interval, therefore, I shall only say a few words. 

 Throughout Lake Keseganaga, a large body of water (long. 91°), as 

 far as I saw, the soil is two-thirds composed of very small primitive 

 pebbles, intermixed with pale brown clay, sand, and angular grit. 



At and about the Fall of Small Pine Rocks, very many large blocks 

 of impure hornblende, quite angular, are found lying on granite. 



On the top of the trappose precipice overlooking Outard Lake, 

 1200 feet above the level of the sea, I found a large block of gneiss, 

 but littb rolled. 



North of the Grand Portage I never met with an erratic from Lake 

 Superior. On the summit level of that Portage, however, are two 

 immense blocks of amygdaloid, similar to that of the Pays Plat of 

 Lake Superior. 



Lake Superior. Loose Detritus of North Shore. — We now pass 



