784 GEOLOGY OF OHIO. 
This has produced much confusion in the search for coal; but all the 
drillers have noticed that the surface of the Waverly is reached at 
various depths, and that hills of “bottom rock” cut out the coal. In 
such cases the coal was never formed on these hills, but accumlated in 
lower ground surrounding them as a bed of peat that reach to a limited 
distance up their side. When subsequently covered by clay, sand, and 
gravel, the peat was compressed to perhaps one-fourth part of its original 
thickness, and formed a bed of coal five or six feet thick in the bottom 
of the basin, and running to a thin edge at the original water level. 
-These irregularities in the surface of the Waverly have been sometimes 
attributed to disturbances and upheavals, but if they were folds in the 
strata the coal would be carried up with the Waverly; but since we 
find the Waverly hills composed of undisturbed and nearly horizontal 
layers, and the coal not reaching the tops of the higher ones, we must 
conclude that they are the result of erosion, and that before the deposi- 
tion of the coal the surface was worn into hills and valleys much as 
now. 
~ 
CONGLOMERATE. 
Probably but little of the area of Mahoning county is underlain by the 
Conglomerate. Patches of it are found in the northwestern corner, and 
these may extend for a long distance southward; but the great sheet of 
Conglomerate which occupies Geauga and the northern part of Portage 
county, thins out rapidly toward the east, and between Niles and the 
State line it either does not exist, or is represented by a thin bed of 
sandstone without pebbles. 
COAL NO. lL. 
This is the seam which furnishes the famous Briar Hill or Mahoning 
coal, so extensively used for iron smelting, and widely distributed 
through the markets of the northwest. Itis the same seam that is so 
largely worked in western Pennsylvania, at Sharon, Greenfield, etc., and 
shipped to Hrie under the name of the Ormsby coal. The true position 
of this coal seam is from twenty to fifty feet above the Conglomerate, the 
interval being filled with shale, sandstone, and fire-clay. In Summit 
and Stark counties, where the same strata are exposed as those which 
form the banks of Mahoning at and below Youngstown, and were the 
Conglomerate is generally from fifty to one hundred feet in thickness, 
the position of Coal No. 1 is clearly shown and is always seen to be that 
described above: In Mahoning county where the Conglomerate is often 
absent form the series, and the Waverly rocks were extensively eroded 
before the formation of the coal, the succession is less apparent and has 
