403 } GEOLOGY OF OHIO. 
When the excitement caused by the discoveries on Oil Creek was at its 
height, the show of oil along the outcrops of this formation did not fail 
to attract attention, and rights to explore and develop the territory were 
bought up through several counties of Ohio and Indiana. Companies 
were formed and wells were sank at several points in south-western 
Ohio. The deepest of these wells was at Eaton, where the boring was 
carried 1,170 feet below the surface. There was, however, no geological 
promise in these undertakings. The Clinton limestone, it is true, is 
rich in petroleum in many localities, but its thickness does not exceed a 
dozen feet, and there have been no disturbances in its stratification by 
means of which reservoirs for the oil have been prepared. When the 
Clinton limestone was passed in the boring, the long series of the Cin- 
cinnati shales and limestones was met with, and the 1,170 feet above 
named were not enough to exhaust the limestone series of the State. A 
considerable fragment of rock was brought up from a depth of 1,130 feet, 
which proves to be a silicious limestone, quite after the pattern of the 
older limestones of the continent in their more northern outcrops. The 
samples of rock saved from different depths in boring were turned over 
to the Geological Survey by the persons who had them in charge, together 
with the records of the company. These latter show alternations of hope 
and disappointment, dependent partly on the geological series traversed. 
The boring was begun in the Niagara, and when the Clinton was reached 
the show of petroleum was sufficient to kindle a blaze of excitement. 
The telegraph was used to announce to distant stockholders the success 
of the enterprise, and the work of boring was temporarily arrested until 
a tank could be provided, so that there might not be “a sinful waste of 
the oil.” 
There are several points in the county which still vield a fine show of 
petroleum, the springs that issue from the base of the Clinton limestone 
being often thickly coated with it. 
As will be seen from an examination of the map, there are numerous 
outliers of the Clinton limestone in the county. The work of denu- 
dation has been carried so far in all of these instances as to entirely 
remove the Niagara beds that originally covered them. 
The great series of the county remains to be mentioned, viz., the Niag- 
ara Group. Its vertical extent seems less than in Clarke and Greene 
counties. There are, at least, no sections furnished like those at Springfield 
and Yellow Springs, in which all the members can be seen 1n one con- 
tinuous exposure. The most considerable section is shown in the bed | 
and banks of Seven Mile Creek, at Eaton. There are nearly fifty feet 
exposed within a mile or two of the village. It is probable that all 
