THE RELIEF FEATURES OF OHIO 



Frank Carney 



Introduction 381 



Composition, structure, and attitude of rocks in relation to relief 



Other influences in relief 



Physiographic regions of Ohio 



River history 

 Remote drainage of Ohio 387 



Early consequent streams 



Adjustments among consequent streams 



Known for merriver courses 



Development of the Ohio river 



Lake Erie (h'ainage 392 



Ohio river drainage 396 



Summary 400 



Lake plain area 



Plateau area 



Altitudes 



Introduction 



The smaller islands of the Pacific are usually divided into 

 two classes: high islands and low islands; these are very simple 

 examples of the relationship between geologic structure and sur- 

 face features. The low islands consist of organic rock, the prod- 

 ucts of coral making animals, whereas the high islands consist 

 of volcanic products. In an area like Ohio, involving over forty 

 thousand square miles, we find no such simple conditions as exist 

 in these Pacific islands. A pleasing variety of relief character- 

 izes this state: in the northwest are gently sloping plains, and 

 in the southeast a dissected low plateau ; the intervening topog- 

 raphy blends easily from one into the other. 



Composition, structure, and attitude of rocks in relation to 

 relief. Geologic processes and results are basal to relief. Rock 

 character is generally an important element in a landscape. 

 What the rocks of an area are, and what has happened to them 

 since they were deposited, are the first questions to ask in account- 

 ing for surface features. 



381 



