384. GEOLOGY OF OHIO. 
the glacier on the unmodified Drift along its foot when in the act of 
retiring. They, however, may be attributed to the action of the water 
_ of the Maumee, instead, upon the glacial Drift at the time of its deposi- 
' tion by the glacier. Its action, however, would be more likely to be 
seen throughout the whole thickness of the Drift, and would not be over- 
lapped by the hard-pan deposits as these laminations are seen to be near 
their junction with the glacial clay. 
The surface of the Drift in various parts of the county has suffered 
considerable denudation since the retirement of the glacier. The waters 
of Lake Hrie formerly covered the whole county, rising about 180 feet 
above their present level. Their prevalence at that height is indicated 
by the following phenomena: 
ist. The rock is laid bare in a great many places, and is wrought 
into fantastic shapes, similar to the surface of rock now undergoing the 
constant beating of the waves. Such water-worn rock is seen nowhere 
in north-western Ohio except along the present lake shore, and at vari- 
ous heights above it up to about 180 feet. 
2d. In the vicinity of these rocky outcrops, known as ‘limestone 
ridges” in the Black Swamp, there are great numbers of bowlders of all 
sizes, and usually of metamorphic rocks. They are thought to be the 
remains of the hard-pan which at first covered uniformly the underly- 
ing rock, the clay and sand having been washed out by the waves. They 
usually lie immediately on the bare rock, and are most abundant round 
the bases of the ridges. They are water-worn and rounded. 
3d. Deposits of fine sand, similar to the subaqueous bars and 
beaches now forming about the shores of Lake Erie, are scattered over 
the whole county, and seem to occupy all heights up to about 180 feet 
above the Lake. They are seen on the elevated portions, that is, on 
those portions which rise somewhat suddenly above the surrounding 
level. Thus they follow, and almost mark out, the eastern border of 
the Niagara area in the center of the county. These sandy deposits are 
not only in the form of isolated knolls, having nuclei of the persistent 
breccia of the Waterlime formation, but are sometimes so continuous 
and regular as to have the name of ridges. Such ridges are met with 
in all parts of the county, running in all directions; and sometimes 
roads have been located on them. The continuous ridge which passes 
through the townships of Bloom and Perry, in.the south-eastern part of 
the county, is not one of lacustrine origin, but is believed to be of the 
same nature as those long gravel ridges seen at higher altitudes in 
north-western Ohio haying the nature of terminal glacial moraines. 
Yet it must have been submerged by the waters of the Lake in some 
