A R T ICLE IX. 



NOTES ON A MAP INTENDED TO ILLUSTRATE FIVE TYPES OP EARTH-SURFACE IN THE UNITED STATES, 

 BETWEEN CINCINNATI AND THE ATLANTIC SEABOARD. 



B Y J. P. L E S L E Y. 



Head May 4th, 18(30. 



VERY little of the topography of America has been published. No large areas have 

 been mapped in such a manner as to show the features of the surface. The State of Massa- 

 chusetts was trigonometrically surveyed, under the direction of Mr. Borden, in 1830; but 

 the published map of that State, which represents the slopes by hachure lines, fails to show 

 the laws which governed the erosion of its surface, and is defective in details. The State 

 of Pennsylvania was not triangulated ; but its topography was carefully studied from 1837 

 to 1841, in sections or districts, by members of the Geological Survey, under Prof. H. D. 

 Rogers ; and these sketch-maps, more or less detailed, were compiled into one State map* 

 which exhibited, for the first and only time, the characteristic features of the topography 

 of the eastern side of the American continent. Although twenty-six other States of the 

 Union have instituted geological surveys, none of them, with the exception of New Jersey 

 and California, has attempted any elaborate topography. In each case the demands of 

 science were supposed to be satisfied with the tracing and coloring of the geological out- 

 crops in a rude and general way. It is especially to be regretted that that accomplished 

 and lamented geologist, Mr. Percival, did not realize upon paper his exact and exhaustive 

 examination of the surface-features of Connecticut, the State which he surveyed, for it 

 could have been done at that time by himself, with ease ; and when done, it would have 

 thrown a flood of light upon some of the most difficult geological structural problems that 

 we have yet to solve. 



It is surprising that no State, except Massachusetts, has ever set on foot a general astro- 

 nomical and trigonometrical survey of its surface. What little of exact determination of 

 latitude and longitude has been accomplished, we owe to the personal labors of Prof. 

 Bache, at first alone, and afterwards with the co-operation of the Coast Survey, of which 

 he is the chief; and to Colonel Graham, Colonel Emory, and other engineers of the U. S. 

 Army, appointed to determine the national boundary lines and to survey the lakes. The 

 last published report of the Coast Survey (Report of Progress for 1863), will show how 



* As I have described in my Coal and its Topography, 1856, Philadelphia. The Stale map was 

 finished in 1811, but not published until 1858. 

 vor,. xjii. — 89 



