1874.] 



287 



[Stevenson. 



readily, but tlie exposures of IV are far from beiuo- continuous, and for 

 miles it does not reach the surface. It is impossible, therefore, to demon- 

 strate the structure, which seems to be as follows : 



What the complete structure of the western portion in the first figure 

 may have been cannot be determined, as erosion has removed all the 

 material beyond the Muskingum River. The direct union of the two 

 beds has not been seen, nor is it likely to be seen, since at all localities 

 where the beds approximate they have a heavy cover. 



Crossing into Pennsylvania, we take the same beds and carry the sec- 

 tion down to the Ferriferous Limestone. The following sections are 

 taken from Rogers' Report * 



Upper Freeport C ! 3' 



Interval Rocks 35' 



Lower Freeport C 4' 



Interval Rocks 1 04' 



Kittanning G 3' 



Interval Rocks 25' 



Ferriferous Limestone j 13' 



In these six sections we find the interval between the two beds varying 

 thus : 184, 143, 142, 117, 109, and 103 feet, while the interval between 

 the Kittaning and the Limestone varies from 55 to 20 feet. 



The accessible records of observations in West Virginia are few, but 

 some of them are of interest. In a repoi-t upon Property belonging to 

 the Pridevale Ii'on Company, and situated a few miles above the junc- 

 tion of Cheat and Monongahela Rivers, Prof. W. B. Rogers gives the in- 

 terval between Upper Freeport and Kittanning, as 160 feet, and between 

 the Kittanning and the Ferriferous Limestone as 50 feet. On Decker's 

 Creek, barely five miles away, I find only 26 feet between the Freeport 

 Coal and the Limestone. The whole group is about 400 feet thick on 

 Cheat river, and only 200 on Decker's Creek, This notable variation oc- 

 curs chiefly between the upper Freeport Coal and the Limestone, as 

 the section below the latter is substantially the same as both localities. 



Going southward, we find the thickness of the whole group rapidly in- 

 creasing beyond the Baltimore and Ohio Railroad, the Upper Freeport 

 Coal still retaining its proper place under the Mahoning Sandstone, and 

 readily ti'aceable to Randolph County, beyond which I have not followed 

 it. Near the State line at the north, the thickness of the group is 200 

 feet, in Randolph County it is not far from 700 feet. Whether or not 

 the coal resting on the conglomerate in Randolph County is the same 

 with that resting on the same conglomerate on Decker's Creek, is quite 

 immaterial. It is quite certain that the interval between the conglome- 

 rate and the Upper Freeport Coal has increased from 200' on Decker's 

 Creek, to nearly 700 feet on the Beverly road in Randolph County. 



The Upper Freeport Coal itself shows a marked tendency to break up 

 * Geology of Pennsylvania, Vol. II, Chaps. 18, 19, 20 and 22. 



