212 GEOLOGY OF OHIO. 
as steep as is to be seen in any mine of the State, and to gain all the 
elevation required to make it normal, within 150 yards of the lowest 
portion of the mine. The interval from the Strip Vein to this portion 
of the mine is not less than 140 feet. 
In structure the Diamond coal agrees in its uppermost 6 feet with 
the structure of the Big Vein at Salineville and elsewhere, as is shown 
in the annexed diagram: 
FIGURE 2OOCOL 
STRUCTURE QF DIAMOND COAL 
SEAM AT LINTON. 
The progress of the mine has shown that this upper portion is in 
reality the normal seam, and that the increase in thickness of this mine 
over other Big Vein mines in the neighborhood is to be found in the 
bottom bench. This sometimes rises to 1 ft. 8 in., and to this extent 
the Diamond coal is re-enforced beyond the Uj.per Freeport measures. 
The coal in the deepest swamp of the mine has been known to measure 
9 feet, but it does not often rise beyond 8 feet. The average of what 
is now worked would be about 6 feet. When it grows thin, as it does 
in every direction from the “swamp,” the bottom bench shrinks, and 
finally disappears altogether. 
In the center of the ‘“‘swamp” of the mine, a bottom bed of cannel, 
4 to 6 inches in thickness, is found, which is of wonderful paleonto- 
logical interest. More than 50 species of fishes and reptiles have been 
