PREBLE COUNTY... All 
Sellers’s Run, near the head of which these quarries are found, fur- 
nishes in its bed and banks an excellent section of the upper rocks of the 
county. Beginning with a fine show of the Clinton limestone, rich in 
its characteristic fossils, which is shown near Turner’s distillery, the suc- 
ceeding beds of the Niagara series to the Cedarville division, inclusive, 
are traversed and disclosed within the course of a mile. 
DRIFT. 
The Drift beds of the county, which may be said to cover its entire 
area, remain to be briefly described. In all of their general characters 
they agree perfectly with the same order of deposits in adjacent regions. 
The bowlder clay, or unmodified Drift, is shown in very numerous sec- 
tions, and is reached in the digging of many wells. In the northern 
half of the county this deposit is uniformly deep—so deep, at least, as 
never to be reached in ordinary sections or excavations. Its surface is 
often covered with the deposits of sand, gravel, and stratified clay which 
compose the modified Drift of this region, and when so covered it consti- 
tutes the water bearer for the area which it occupies. When the bowl- 
der clay itself makes the surface, the water supply is found at easily 
accessible depths within it, in some of the seams of sand and gravel that 
are scattered at irregular intervals through its substance. 
In the central regions of the county the bowlder clay rests directly 
upon the polished surface of the Niagara limestone, and in the southern 
regions it is not seen as distinctly or as often, its best exposures being 
confined principally to the deeper valleys. | 
_ The bowlder clay gives every indication of having a formed under 
the great glacial sheet which has been demonstrated to have covered the 
northern portions of the continent in the period preceding the present. 
It is filled with scratched and polished fragments of limestone and north- 
ern rocks, compactly laid in the dark blue clay which characterizes the 
formations of this age in every part of the world where they occur. The 
seams of sand and gravel interpolated in the clay, doubtless, result from 
partial meltings of the glacial sheet in some of the milder periods of its 
history. The ice-sheet in its southward advance must have found the 
face of the continent covered with a forest growth and other forms of 
vegetation. It seems certain that some remnants of this pre-glacial 
growth are preserved in the bowlder ciay. Worn fragments of wood, at 
least, are often found deep in the clay, which it seems impossible to refer 
to any other source. 
This pre-glacial vegetation must not, however, be confounded with the 
interglacial growths to which attention has often been called in the 
