0 N T H E SOUTH S H ORE 0 P LAKE S U P E R I 0 R. 



427 



miles above its junction with the main or Middle Fork, is a ductile clay, that becomes 

 hard and tough at a moderate heat in a common fire. On the " Isle aux Barques," 

 the lime was so abundant that it had formed in amorphous concretions throughout 

 the mass. A very few leaves and decayed sticks have been seen in these red, marly 

 clays, with carbonaceous matter and lignite ; but such organic contents are not of 

 usual occurrence. 



Along the coast there are interstratified beds of sand and gravel of a local cha- 

 racter. The section given by Mr. Randall, in the Report of 1847, and those I give 

 below, illustrate this fact. In the interior, where the clay is visible in bold bluffs, 

 along the water-courses, it is more uniform and less intercalated with coarse drift. 

 It rests not only on the sedimentary unaltered rocks, but also on trap and meta- 

 morphic and igneous rocks, as may be seen by consulting Sections 1, 2, 3, 4, W. 



The bold and curiously wrought face of the clay bluffs on the coast form scenes 

 that attract the attention of the traveller, and are worthy the notice of the scenic 

 painter. 



The following sections of the quaternary deposits on the south shore of Lake 

 Superior and the adjacent islands, will give an idea of their relative position and 

 thickness. The first was measured at the north end of Oak Island ; the second at 

 the bluffs one mile west of Pointe Ecorse, or Black Point ; and the third is a section 

 of three miles, from the coast to the mountains, four miles southwest of La Pointe. 











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1 



1. ii. Coarse boulder drift, extending in the rear to the summit of the island, three hundred feet above the Lake. The slope of this exposure 

 is 3S°, its foot protected from the waves in some degree by the boulders that fall from the bank. b. Sand, thirty-five to forty feet. c. Red 

 clay and boulders, twenty-five feet. d. Red and gray sand, twenty feet. e. Red clay and boulders, seventy-five feet. The total height above 

 the Lake is one hundred and seventy-three feet. This section represents all the beds of this formation seen on the shore of Lake Superior. 



2. a. Sand and clay, twenty feet. h. Gray sand, sixty feet. o. Red homogeneous clay, fifty feet. Total height above the Lake, one hundred 

 and thirty feet. 



3. d. Coarse boulder drift, the top of which is four hundred and twenty-eight to five hundred and nine feet above the Lake. <-. Red marly 

 clay, ninety-five to one hundred and thirty feet above the Lake. s. Red and variegated sandstone, on which the red clay reposes. 



This last section commences at the Lake near the mouth of a creek, which my 

 half-breed voyageurs said was called by the Chippew T as, Che-me-tau-gon-sibe ; by 

 the whites, Prairie River ; and extends through the red clay to the top of the moun- 



Protoxkle and peroxide of iron, soluble in bydrocblorie acid 





before fusion 



witb carbonate of soda, 



9-2 







after " 



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1-5 













10-7 



Lime, " 



" before " 



ft u 



4-7 





It u tt 



" after '• 



tl 11 



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54 



Magnesia, " " 



" before li 



li it 



2-6 





tt tt u 



after 



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3-3 



Loss, 









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