GEOLOGT. 41 



PKIMITIVE ROCKS- 



These are discovered, as soon as we have ascended the sec^ 

 end ridge, south of lake Erie, as we travel southwardly. 

 They consist of granite, sienite, black mica, and indeed eve- 

 ry variety of mica slate, gneiss, and all the primitive rocks 

 of this continent. They occur in amorphous masses, abrad- 

 ed, and smoothed, by friction, and show conclusively, that they 

 are out of place, and are unconnected with any other rocks 

 in, or near, where they now lie. They are generally, at an 

 elevation of about seven hundred feet, above the present sur- 

 face of the ocean. But where the earth has been worn away 

 by some stream of water, near them, they have, in some in- 

 stances, been undermined, and have fallen down, on a lower 

 level. These boulders, are found in large masses, covering 

 in some places, several acres, reposing on the north sides of 

 hills, of a diluvial deposite. They are rarely found on the 

 southern ends of hills, unless removed thither, by some more re- 

 cent revolution, than the one which deposited them originally in 

 this country. These primitive rocks, we have seen all along 

 the southern shores of the northern lakes, from the east end 

 of lake Ontario, to the western side, of the southern end of 

 lake Michigan. They are uniformly found at about the same 

 height, unless removed by some force more recent, apparent- 

 ly, than that, which, originally deposited them in this region. 

 From east to west, they extend, at least eight hundred miles, 

 in a right line. Their elevation is everywhere, nearly the 

 same, above the present surface of the ocean, and they are 

 most numerous, on the northern ends of hills, pointing a little 

 east of north — about three points of the compass- 

 When we say, that these rocks are found, thus, in a line 

 extending from the lower end of lake Ontario, to the western 

 side of the southern end of lake Michigan, we do not say, 

 that these rocks are not found, east and west of these limits. 

 But, thus far, we have seen them, and have carefully examin- 

 ed them, in person, and have noticed, carefully, every circum- 

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