tJNiTED States* 



the chains of Gauley and Laurel Hill, which are 

 rocky and dry. 



Toward the north-west, that is on the side of the 

 lakes of Genessee, Ontario, and Erie, the sandstone 

 terminates in a region of slaty schist and blue marie, 

 ■which is pretty extensive, for it appears to form the 

 bed of these lakes, as appears from soundings taken 

 in them, and the stones at their bottom and in their 

 banks. They extend even over the beds of coal m 

 West Pennsylvania, This marie is full of fossil 

 shells. Ledges of these schists are found again at 

 Niagara, and all along the St. Lawrence, as far as 

 Quebec. We have seen too, that they pave the bed 

 of the upper part of the Hudson. These are their 

 most extensive known domains ; elsewhere they are 

 seen only in small patches. 



Besides this vast region of sandstone, somei districts 

 of the same nature may be mentioned ^dispersed 

 through the granitic and calcareous regions ; but 

 there in turn they form exceptions. Such is that of 

 the county of Worcester in Massachusetts, the most 

 extensive of the kind known. This cannot be re- 

 ferred to the Alleghanies, unless its continuity across 

 the rivers and country of Connecticut and the Hud- 

 son could be shown. 



3. Calcareous Region. 

 The third region, that of calcareous earth, includes 

 all the Western or Back Country, lying behind the 

 Alleghany mountains, and extends north-west, ac- 

 cording to the information of Mr. Mackenzie, across 

 thi rivers aid lakes to the sources of the Sakatchie, 

 the chain of the Chipewyan mountains* 



