UNSTRA.TIFIED ROCKS. 223 



northern section of New- York as far to the north- 

 west as the St. Lawrence river, consists of primary 

 rocks, with the exceptions we have already pointed 

 out, and shall more particularly describe under Sec- 

 ondary/ Rocks, 



Primary rocks also compose a principal part of 

 the materials of the range called the Ozark Mount- 

 ains, west of the Mississippi ; and far off on the 

 western side of the continent, in the vast chain of 

 the Rocky Mountains, they exist in promiscuous 

 profusion, constituting far grander phenomena than 

 belong to any part of the range skirting the Atlan- 

 tic. Extending far to the northwest, we then trace 

 the primitive range, in the shape of low hills, with 

 rounded summits, and more or less precipitous sides, 

 across the continent to the shores of Lake Superior, 

 forming a belt of about 200 miles in width. 



Unstraiijied Rocks. — The greater portion of the 

 primary rocks of the Eastern States belong to the 

 stratified class, such as gneiss^ mica slate ^ &c., and 

 those of the Middle and Southern States consist of 

 this class exclusively. The unstratified rocks of 

 the United States occur chiefly in the country east 

 of the Hudson River, and, as we have already stated, 

 may be included under four varieties, viz., granite^ 

 syenite, porphyry, and greenstone. These are dis- 

 tributed in numerous isolated patches among the 

 stratified rocks throughout the whole of the New- 

 England States, but particularly in the eastern part 

 of Massachusetts and in the vicinity of Boston, 

 where they occupy more than half the surface. 

 They also stretch up along each side of the Con- 

 necticut River, at a distance of from 5 to 20 miles, 

 enclosing the new red sandstone, and giving pecu- 

 liar features to this beautiful portion of country. 



The granite of New-England is thus distributed in 

 such irregular patches and so many isolated ranges, 

 that it is impossible, within the compass of a work 

 like this, to give anything like a correct delineation 



