696 GEOLOGY 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. Iam inclined to the opinion that his explanation is cor- 
rect, but that the greatest difference 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 Creek 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, fhe) coal shows the fol- 
lowing sections: 
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