696 GEOLOG"? OF OHIO. 



It is here called the " six and a half feet coal," and averages about that 

 thickness. 



This diminution of thickness is local, and on the south side of the 

 Hocking it increases to eight feet, but the thickening up in that direction, 

 as well as in all the territory east from Moxahala to the Hocking, is due 

 almost wholly to the increased dimensions of the middle and lower 

 benches, as the sections given by Professor Andrews, and in this report, 

 clearly show. 



Mr. Roy, the State Inspector of Mines, attributes the diminished thick- 

 ness here to the splitting of the upper bench by a local submergence of 

 the old coal marsh, which brought in a wedge-shaped deposit of mud, and 

 has left a bed of shale twenty feet thick at Haydenville, ten feet at 

 Brooks's mine, four feet at Longstreth's, thinning out and disappearing 

 near Doanville, the growth of the coal vegetation being at this time un- 

 interrupted in the rest of the marsh, and gradually spreading over this 

 submerged position, leaving a thin bed of coal, which, in places, is 

 twenty feet above the Great Vein, and in others constitutes a part of the 

 upper bench. I am inclined to the opinion that his explanation is cor- 

 rect, but that the greatest diflerence in the thickness of the coal is not 

 to be attributed to this cause. The thickest coal is on a line running 

 north and south through the western parts of Monroe and Trimble town- 

 ships, and here the combined thickness of the two lower benches is, in 

 places, nearly ten feet. This thickening of the lower benches indicates 

 the deeper parts of the original coal marsh, which was comparatively 

 shallow in Salt Crqek and Ward townships, where the lower benches are 

 thinner. 



In the eastern part of the coal basin, where the whole coal is the 

 thickest, the upper bench is comparatively thin. It has its maximum 

 thickness about Shawnee and Straitsville, and from thence down the 

 Snow Fork to Doanville, and along this line the deposition of vegetable 

 matter forming the upper bench continued, after it had ceased in other 

 parts of the field. The local thickening of the upper bench is apparently 

 due to this cause ; the increased thickness of the two lower benches can 

 not be so explained, but simply indicate the deeper parts of the old 

 marsh. 



South of the Hocking the coal becomes thicker than at Nelsonville, the 

 increase being in the lower benches, so that the conditions during the 

 deposition were there similar to those in the west parts of Trimble and 

 Monroe townships. 



On Meeker's Run, Section 16, York township, the coal shows the fol- 

 lowing sections : 



