194 GEOLOGY OF OHIO. 
diate vicinity as a cement rock. Finally, the Ferriferous limestone is 
found covering the Creek Vein coal in numerous sections. It is blue 
in color, not more than 3 feet thick at any point, and charged with 
characteristic fossils. 
Of the five seams named above, the second and the last furnish all 
the coal that comes out on the railroad between Leetonia and New 
Lisbon. Three shipping mines are opened on the Big Vein, and one 
on the Upper Clarion seam. The former are named the Wolf Run, 
Shelton and Maple Hill mines; the latter is known as the Rock Hill 
mine, and belongs to the Niles Mining Company. The coal of the Big 
Vein is of the usual character, a strong and serviceable fuel, with 
rather a high percentage of sulphur. Thin seams of shale occur at 
irregular intervals, which increase the ash of the coal at times beyond 
the usual limits. 
The coal of the Rock Hill mine (Upper Clarion or Canfield Can- 
nel) is highly cementing, and ranges in thickness from 2 ft. 6. in. to 
3 ft.10in. It is without regular partings. It isa “hilly” seam, the 
floor being very uneven. Above the coal is a “draw-slate,” 8 to 12 in. 
thick, black and highly fossiliferous, and charged with cone-in-cone. 
This slate represents the Ferriferous limestone in numberless sections 
throughout the region. The coal contains large balls of pyrites, of the 
kind known as “black sulphur.” ‘These masses are sometimes 12 or 
14 inches in thickness, and weigh many hundred pounds The fire-clay 
beneath the coal is of excellent quality, and has long been worked in 
this vicinity. It ranges from 1 ft. 6 in. to 4 ft. in thickness. Under 
the clay the seam of coal that has been shown in so many other instances 
occurs. 
At one point in the mine, in digging a “sump,” this lower seam 
was found 20 inches thick. The coal, however, is poor, and it is never 
taken out. 
The mine is entered by a slope, the coal lying at and below the 
level of low water in the creek, and under a heavy hill. On account 
of its situation and character it accumulates fire-damp, and one of the 
most destructive explosions of Ohio mines occurred in it a few years 
ago. Since that time it has been under more careful management in 
this regard. 
The section that includes the coal is an interesting one. It is 
shown in Fig. XX VI. It requires no comment. 
