in North-Eastern Amernca, 



7 



subdivision — partially overlapping and rising- above eacli other 

 in a succession of small but distinct terraces of greater or less 

 breadth — plainly exhibit to the eye of the observer the chemical 

 characters of each, the kind of soil which in crumbling it na- 

 turally produces, and the special effect it has on the agricultural 

 capability of the surface that rests upon it. 



The country to which I here lefer extends along the southern 

 shores of Lake Ontario, from beyond Buffalo, at the foot of Lake 

 Erie, on the west, to Oswego, near the foot of Lake Ontario, on 

 the east. Its length is about 180 miles, and its mean breadth 

 from Lake Ontario towards the south about 30 miles. The 

 district rises as we proceed southward from the Lake, sometimes 

 by sudden starts over rocky escarpments, but generally in a 

 gradual manner, till it attains a height of 600 or 700 feet above 

 the Ontario. Farther south, towards the Pennsylvanian border, 

 the high land attains an elevation in some places of nearly 2000 

 feet. The woodcut (p. 8) exhibits an outline of its geographical 

 position and geological structure. 



This outline map shows the relative position of the Lakes Erie 

 and Ontario, the discharge of the waters of the former into the 

 latter by the Niagara river, and the drainage of the high southern 

 country towards the borders of Pennsylvania by the Genessee 

 river, which falls into Lake Ontario below Rochester. The 

 lines which run from east to west indicate the boundaries of the 

 several rocky formations of which the country consists ; all, 

 except that marked 8 and 9, belonging to what is called in 

 Europe the Silurian system of rocks. The area or strip of country 

 covered by each formation is represented by the numbers 1, 2, 

 3, &c., in the ascending order of their superposition. They form, 

 as I have above stated, a succession of strips, belts, or terraces, 

 of greater or less breadth, from the lowest (No. 1), on the banks 

 of the Lake, to the highest (No. 9), which covers the interior of 

 the country. The names given by the New York geologists to 

 these several rocks are as follows : — 



No. 1. The Medina sandstone; No. 2. The Clinton group; 

 No. 3. The Niagara group ; No. 4. The Onondaga salt-group ; 

 Nos. 5 and 6. The Helderberg group ; No. 7. The Hamilton 

 group ; Nos. 8 and 9. The Portage and Chemung groups. 



The broadest belts, as will be seen from the map, rest upon 

 the Medina sandstone and on the Onondaga salt-groups. Of 

 course I do not compare any of these belts in area with the 

 extended surface occupied by Nos. 8 and 9, which bound on the 

 south the low and fertile region to which my observations will 

 chiefly apply. The mineralogical character of these several 

 groups of rocks, viewed in connexion with the nature of the soils 



