402 Frank Carney 



change uniformly upstream, a condition which reflects the river's 

 composite origin; the divides between the segments of the streams 

 which were united in forming the Ohio river are characterized by 

 more youthful dissection. Throughout the whole of the plateau 

 area the streams are fairly well adjusted to the rock structure. 



Altitudes. Ohio has an altitude range of about 1100 feet. The 

 highest point, 1540 feet, is in Logan county; the lowest, 440 feet, 

 is the low-water mark at Cincinnati. The Ohio river drops about 

 220 feet in the 436 miles of its course along the state. According 

 to the Dictionary of Altitudes^ the following are the altitudes 

 for the low-water mark at various points upstream from Cincin- 

 nati: Maysville, Ky., 448; Portsmouth, 468; Ironton, 483; Mari- 

 etta, 570; Moundsville, W. Va., 614; Wheehng, W. Va., 622; 

 Steubeifville, 641. The Wellsville topographic sheet shows the 

 660-foot contour crossing the river at East Liverpool. 



Lake Erie is 573 feet above sea level; within the lake plain 

 region are included the adjacent areas below 800 feet in altitude. 

 A relief map of the state shows that the plateau area consists of 

 five north-south blocks that are over 1000 feet high; these are 

 separated by lower strips through which flow the important rivers 

 of the state. In the south central part of the state, between the 

 valleys of the Scioto and the Muskingum, the general altitude 

 is less than 1000 feet. The north-south blocks of higher altitude 

 increase in surface irregularity and in irregularity of outline from 

 west to east; the most eastern block does not contain any east- 

 west gaps north of Washington county. The general parallelism 

 of these blocks, their ragged outlines, and the intervening lower 

 strips, have exerted a strong influence in the industrial develop- 

 ment of Ohio. 



* U. S. Geological Survey, 1906. 



