270 GEOLOGY OF OHIO. 



put in an appearance in a particular section, thus bringing, in apparently 

 consecutive order, elements that are separated in nature by well marked 

 intervals. 



Coal Seams of Ohio. 



Washington coal. 



Waynesburgh " 



Sewickley " Macksburgh or Meigs Creek. 



Pittsburgh " 



Crinoidal Limestone coal. 



Patriot coal. 



Cambridge Limestone coal. 



Mahoning " 



Upper Freeport " 



Lower Freeport " 



Middle Kittaning " 



Lower Kittaning " 



Clarion " 



Brookville " 



Tionesta " 



Upper Mercer " 



Lower Mercer " 



Quakertown " 



Sharon " 



Coals above the Pittsburgh as named by Prof. I. C. White, Bulletin 

 65, U. S. Geol. Survey are as follows : 



Nineveh coal. 



Jollytown " 



Washington " with several splits. 



Wayeusburgh" " " 



Uniontown " 



Sewickley " 



Redstone " 



We are obliged also, by the requirements of geology, to adopt the 

 divisions of the Carboniferous System that were established in Penn- 

 sylvania. It is certain that the column would have been somewhat differ- 

 ently dealt with if its subdivisions had been first established in Ohio. 

 But all the boundary lines of the Pennsylvania system can be plainly 

 enough followed here when our atcention is directed to them. Against 

 one division only, have we even any apparent ground of complaint. 

 Moreover, the entire system is much more fully expanded in Penn- 

 sylvania than in Ohio and on this account, the former state furnishes the 

 best grounds for making out the true order. The main divisions, which 

 were established by Rogers and his assistants, in the First Geological 

 Survey of Pennsylvania, have been universally adopted by the geologists 

 of the Appalachian coal fields. They are as follows : all of the divisions 

 being represented in Ohio. 



