250 



The Up])er Coal Measures 



The relative geographical positions of these localities, as 

 well as those of some others already referred to, are shown 

 in the following diagram. 



Barnesville.* 



* Scott's RuD. 



A similar series of sections of the Barren measures shows 

 that the strata of that group diminish in thickness east and 

 west of the central portion of the basin. There can be no 

 doubt, therefore, that at the beginning of the Barren epoch, 

 the Alleghany basin had already its present shape and was 

 bounded on the west by the slopes of the Cincinnati axis, 

 on the east by the slopes of a similar axis. The events of 

 the succeeding epoch seem to show that the Cincinnati axis 

 had attained its highest elevation before the deposition of the 

 upper coal measures began. At the close of the Barren 

 epoch, the northern portion of the basin was a half-filled 

 valley such as is now presented by the bed of the Ohio river, 

 below Smith's Ferry. 



A comparison of the upper coal measure sections given 

 above, shows that as we leave the middle of the basin we find 

 the limestones diminishing in every direction. In the portion 

 below Coal X, these limestones, followed west and north do 

 not give place to otf-shore deposits, but simply disappear 

 and permit the coal-beds to approach each other ; whereas, 

 eastward, they interlock with sandstones and shales, before 



