8 WRITINGS OP JOSEPH HENRY. [1824- 



TOPOGRAPHICAL SKETCH OF THE STATE OF NEW-YORK, DE- 

 SIGNED CHIEFLY TO SHOW THE GENERAL ELEVATIONS AND 

 DEPRESSIONS OP ITS SURFACE. 



(Transactions of the Albany Institute, vol. I, pp. 87-112.) 

 Read October 28, 1829. 



The Topography of the state of New-York, viewed either 

 in relation to that of the continent of North America in 

 general, or only in reference to the space included within its 

 own political boundaries, presents many interesting and pe- 

 culiar features. 



The two great lakes, and their outlets, forming a natural 

 boundary on the north and west; the continued chain of 

 water communication of the Hudson and Lake Champlain, 

 along the whole eastern section ; the connected series of 

 smaller lakes in the interior, together with several large 

 streams which rise in the middle of the state, and pass 

 through its southern boundary ; all give to the surface of 

 New- York a diversity of aspect, and a facility of internal 

 navigation, possessed by no other section of our own coun- 

 try, and perhaps not surpassed by any of equal extent on 

 the surface of the globe. 



The eastern portion of the United States, designated by 

 geographers as the Atlantic slope, is separated from the cen- 

 tral part, or the great valley of the Mississippi, by a marked 

 natural division, consisting of a continuous swell or ridge of 

 land extending from Alabama to the south shore of Lake 

 Ontario. This ridge is the true water shed of the country, and 

 determines the course of the rivers falling into the Atlantic 

 on the one side, and those into the Mississippi on the other. 

 It has a mean height of about 3000 feet; and cannot be 

 crossed at any point south of the state of New-York, by an 

 elevation of less than two thousand feet above the ocean. 

 Upon the acclivities of this ridge are based an indeterminate 

 number of spurs, hills, and collateral subordinate ridges, 

 which often rise to a much greater height than the crest of 

 the water shed. These subordinate ranges are not continuous, 

 but are often cut through by the Atlantic rivers : They have, 



