walcott.) LAKE SUPERIOR SANDSTONE. 189 



So far as my examinations during the past year have extended the rock is destitute 

 of fossils, and in fact after a careful examination (several years ago) along its whole 

 line of outcrop, on the southerly shore of Lake Superior, I have never been able to 

 detect in the rocks a single contained fossil. 1 



The fourth report describes the "lower or red sandstone and shales" 

 as follows : 



The red sandstone, with its accompanying red and gray shales, occupies a much 

 larger extent of the country bordering upon Lake Superior than any other single rock 

 or group of rocks. It rests upon the primary aud raetamorphie rocks immediately 

 west from Chocolate River; upon the conglomerate aud mixed rocks from near Eagle 

 River, of Keweenaw Point, west to the head of Lake Superior; upon the primary 

 trap, metamorphic and conglomerate rocks of the north shore of the lake, and upon 

 the conglomerate rock of Isle Royale. It is this rock which forms the basis of the 

 level plateaus or valleys occupying the spaces between the several ranges of hills 

 south from Lake Superior, and west from Chocolate River. In these last situations 

 this rock is frequently seen undisturbed to surround the bases of isolated knobs of 

 granite, though when near to or in contact with knobs or [of] trap there are invari- 

 able evidences of very great disturbance. 3 



A second bed of sandstone is described as the "upper or gray sand- 

 stone." " Upon the shore of Lake Superior, and extending from Point 

 Iroquois to Grand Island, a sandstone occurs, differing widely in its 

 appearance from that before described. This sandstone rests uncon- 

 formably upon the red sandstone, the former dipping gently to the south 

 or southeast, while the latter dips very considerably to the north or 

 northwest." 3 



A sandy limerock rests conformably and immediately upon the upper 

 or gray sandstone. The tabulation of the rocks of the Upper Peninsula 

 is as follows: 4 



9. Tertiary clays and sands. 



8. Upper limerock group (embracing as members the Drummond Island 



and Mackinaw limestones). 

 7. Lower lime rock and shales. 

 6. Saudy or intermediate limestone. 



Thickness. 



5. Upper or gray sandstone, mean feet.. 700 



4. Lower or red sand rock and shales, extreme do... 6,500 



3. Mixed conglomerate and sand rock, extreme do... 4,200 



2. Conglomerate rock, extreme do. .. 5,260 



1. Metamorphic, trap, aud primary rocks. 



A detailed account of the red saudrock and shales is given on pages 

 37 to 41. This is followed by a description of the upper or gray sand 

 rock, of which he says : 



The only remaining rock which separates the red sandrock from the limestone lying 

 to the south is a gray or brownish sandrock that is almost wholly composed of 

 grains of quartz, usually feebly cemented with calcareous matter. The composition 

 of this rock differs from that of the lower sand rock in being more exclusively quartz, 

 while in epoch of deposition the rock under consideration should not be confounded 

 with that of the red sandstone. It has already been stated that the red saudrock of 



»Op. cit., p. 15. a Op. cit., p. 19. 



a Fourth Ann. Rop. State geologist of Michigan, * Op. cit., p. 22. 



1841, pp. 18, 19. 



