10 



PHYSICAL GEOGRAPHY OF 



The elevation of low water in the Ohio at Pittsburg is variously stated by 

 different authorities. Preference is here given to the levels made under the 

 direction of Messrs. Nathan S. Roberts, and Alfred Cruger, in 1829, for the 

 Chesapeake and Ohio Canal Company. 



The elevation of the low water surface of the Mississippi, at the mouth of the 

 Ohio, is derived from the recent survey of the Mobile and Ohio railroad, made 

 under the direction of Captain John Childe, civil engineer. 



The level of Lake Erie which forms the basis for the determination of heights 

 west of the Ohio, was first correctly obtained in the location of the Erie canal, 

 and reported at 565 feet above tide. 



The elevation of that lake, as determined by the survey of the New York and 

 Erie Railroad, was 569 feet above tide. 



The following table exhibits the elevations of prominent points along the 

 Ohio and Alleghany rivers above the level of the Atlantic. The writer regrets 

 his inability to give to the respective engineers by whom the surveys were made 

 proper credit for their labors. 



TABLE II. 

 ELEVATIONS OF THE OHIO RIVER AT LOW WATER. 



Mouth of Ohio, above high tide, in Gulf of Mexico 



Mouth of Wabash, (approximately) 



Evansville, (approximately) - . - . 



New Albany, below the Palls - 



Louisville, above the Falls - . - . 



Cincinnati --.-.-_ 



Portsmouth ------- 



Mouth of Great Kanawha - . - - 



Head of Le Tart's Shoals - - - - 



Marietta, (mouth of Muskingum) - - - 

 Wheeling ------- 



Pittsburg ------- 



Franklin -----._ 



Warren ....... 



Chautauqua Lake ------ 



Olean Point ------- 



Mouth of Oswaya ------ 



Smithport ------- 



Coudersport ------- 



Surface of Lake Erie ----- 



275 



297 



320 



353 



377 



432 



474 



522 



555 



571 



620 



699 



960 



1,187 



1,306 



1,403 



1,419 



1,480 



1,649 



565 



