MASSILLON COAL FIELD. 775 
1. STRUCTURE OF THE MASSILLON CoAL FIELD. 
As is the case with the Sharon coal seam elsewhere in Ohio, the 
coal of the Massillon field is in all cases disposed in distinct basins or 
troughs, which range in size from a few acres up to a few hundred, but 
rarely exceeding two hundred acres; the greater number range between 
30 and 70 acres. Each basin or trough holds a lenticular body of coal, 
the thickest part of which is generally at the center or along the axis 
of the basin, and which is known among the miners as the “swamp” of 
the seam. Toward the margins of the basins, the coal grows thin, some- 
times gradually, and sometimes by rapid reduction in volume. As the 
seam is seldom followed by the miner when it runs below 2 feet in thick- 
ness, it is quite possible that some of the basins that appear to be distinct 
may in reality be connected through a thin sheet of coal that stretches . 
over the “hills” of the mines. These basins are frequently grouped in 
close proximity, to the extent of a half dozen or more, but some appear 
to be separated by wide intervals from any other bodies of coal. 
There is apparently a normal or regular thickness of the seam, for 
the swamps of all the important basins generally show about 5 feet of 
coal. The better mines yield about 4,500 tons to the acre by the 
present system of working. 
The coal of the several basins is laid upon an uneven floor, and 
considerable differences of level are due to this fact, but in addition to 
this, the basins as a whole share in the inclination of the whole series 
of rocks in which they are included. In general terms, the dip of the 
coal may be said to be to the southeast, but there are many local excep- 
tions to this statement. The margin of the Coal Measures is a sinuous 
one, and this fact is not altogether due to the accidents of atmospheric 
waste and erosion, but it seems to go back to original conditions of 
deposit. The dip of the coal basins adjusts itself in part to this 
margin, being generally at right angles to it, but in the large way 
all of them incline to the south and southeast. 
The facts of the dip can be learned from an examination of the 
accompanying chart, which was prepared by Mr. James Nichols, under 
Dr. Newberry’s direction. It is entitled Map showing Elevations of 
Massillon Coal, ete. 
The elevations of the coal are also shown herewith in tabular 
arrangement, to facilitate reference. 
Beginning at the Akron mines, we find the following series: 
