ON THE ORIGINAL COXNECTIOX OF THE EASTERN AND 

 WESTERN COAL-FIELDS OF THE OHIO VALLEY. 



Among all the debated matters concerning the development of American 

 geography, perhaps none have been the subject of a more extended discus- 

 sion than the question of the original relation of the several coal-fields of 

 the cai'boniferous era that lis wuliin the T'alley of the Mississippi. On the 

 one side it has been maintained that those areas were originally parts of 

 one and the same field, owing their separation to the wasting they have 

 received ; on the other, that they were, from the beginning, distinctly sep- 

 arated areas, and have had their physical and vital problems as individu- 

 alized as are those of fv'idely separated seas. 



It has been especially contended, and this with a great deal of vigor and 

 effect, that the eastern and western basins of the Ohio Valley, commonly 

 known as the Appalachian and the Illinois fields, were, at their time of 

 formation, separated from each other by the ridge known as the Cincin- 

 nati axis. 



A careful study of this problem in the State of Kentucky, where alone 

 exists the data for its solution, has served to convince me that there is a 

 considerable eiTor involved in this generally accepted opinion, an error 

 likely, if it continues unassailed, to confuse all our notions of the geologi- 

 cal history of the continent. I shall therefore set forth in brief the nature 

 of the evidence that has led me to the opinion that these coal areas, lying 

 to the east and west of the Cincinnati anticlinal, were not only originally 

 united into one area, but were actually connected down to a very recent 

 time, in the geological sense of the word. 



A reference to the geological map of Kentucky, published by the Sur- 

 vey, will show that these two fields have now their nearest escarpments 

 within less than eighty miles of each t»ther. It will also show that there 

 are many over-outliers, which are clearly relics of a once continuous field, 

 which diminish the gap between these coal basins, so that at one point 

 it is not over forty miles between the outlying remnants of either field. 

 Standing upon the heights of either escarj^ment, the eye ranges over the 

 intervening country to the outliers on the other side. A little observa- 



