SOURCE OF ST. Peter's river. 201 



vegetation, appeared to indicate a difference in their ge- 

 ological character. 



The Pointe aux chenes, or Oak point, may be considered 

 as the commencement of St. Mary's river, which at the 

 Pointe aux Pins, one mile lower down, is about three 

 miles wide, and has a rapid current and a devious bed. 

 The wind being fair, we spread a sail, and in two hoars' 

 time reached the head of the rapid which is termed the 

 Sault de St. Marie. We landed, left our boat, and walked 

 along the Portage road, on the south bank of the river, 

 to the " Cantonment Brady," which is the highest military 

 post occupied by the United States' troops on the chain of 

 lakes. A mill-race has been dug from the head of the rapid 

 to the fort ; it is somewhat less than a mile long ; it dis- 

 closes the nature of the rocks, which consist of red sandstone 

 horizontally stratified. This was the first spot at which 

 we observed this rock in place, but Dr. Bigsby has inform- 

 ed us that he found it in man}^ of the spots at which he oc- 

 casionally encamped on the north shore of the lake. In 

 Mr. Schoolcraft's narrative we are informed that this rock 

 extends to a very considerable distance along the south 

 shore of Lake Superior. The canal or mill-race, which the 

 garrison has opened at the Sault, has been made with 

 much less difficulty and expense than would at first have 

 been expected, from the apparent magnitude of the under- 

 taking; at a very slight additional expense the canal might 

 be enlarged so as to render it navigable for bark canoes of 

 the largest size. 



Our party travelled the distance from Fort William to 

 the Sault de St. Marie in fifteen days ; this passage was 

 considered very short considering the season. An idea 

 can be formed of our success in this respect from the cir- 

 cumstance that the superintendent of Michipicotton house. 



