530 GEOLOSY OF OHIO. 
In the eastern, and especially in the north-eastern and south-eastern 
parts, the surfaee is hilly and broken, and the erosion of the Coal Meas- 
ure rocks has left a succession of terrace-like benches, which characterize 
the hilly regions of the coal-fields of the State. 
In protected places the drift clay covering still remains in these hilly 
regions, and sometimes caps the highest hills. Hast of Mt. Haton, an ex- 
cayation for coal discloses 
Nellow drift’ clay. oe lou. sist es ie cere eed ter apercleve a mereapey teres eee aye as 12 feet. 
Blue CE ech Str Ike lara ies ep latmiia Seva ne ierchreta fatale Rate slate te ie ope teyeteet te caretenete Heese Giriay 
Both members containing striated pebbles of the blue limestone, which 
is in bed on this horizon, and rounded pebbles of granitic rocks. The 
surface deposits in the central and western parts of the county are simi- 
lar to those described in the preceding counties. Between the streams 
an undulating and billowy surface of yellow clay, with blue clay below, 
may be seen resting, sometimes directly upon the bed-rock, sometimes 
with a bed of gravel interposed. On the margins of the streams and old 
pre-glacial channels are sand and gravel ridges, and in the valleys allu- 
vium, resting upon beds of lacustrine clay, gravel, or bowlder clay, some- 
times over one hundred feet in depth. 
GEOLOGICAL STRUCTURE. 
A small portion of the northern parts of Canaan and Milton townships, 
the greater part of Chippewa and Baughman, all of Sugar Creek and 
Paint, the greater part of East Union and Salt Creek, and a small por- 
tion of Green, Franklin, and Clinton townships are covered by the coal 
formation. All the rest of the county is Waverly, as indicated by the 
shading upon the map. This western margin of the coal rocks is by no 
means coincident with the western margin of the coal, as the sandstone 
belonging above the Upper Coal is in places found resting directly upon 
the Waverly, without coal, coal shale, or fire-clay to mark its horizon. 
The brown shading indicates, as accurately as could be determined, 
the territory covered by rocks belonging above the Sub carboniferous 
Conglomerate, which is h-re not continucus, and is colored red. Along 
parts of this western margin heavy beds of Drift mark the geological 
structure, and the line is located approximately, as the topography and 
the nearest outcrops of the rocks indicate its position. 
A section from Mt. Eaton to the bottom of the valley at Fredericks- 
burgh would expose all the rock strata of the county, from Coal No. 7, at 
the top, to the Waverly. 
