STATE GEOLOGIST. 63 
reported north of Bloom, Henry and Liberty townships. The third pay 
was not discovered until about 1900. In parts of Wood county many 
wells are being drilled deeper with the hope of striking the second or 
third pay. 
Another characteristic of the Trenton in the vicinity of Welker and 
Bairdstown is the presence of numerous crevices. These are reported 
in nearly every oil field, but are usually looked upon with much suspicion 
by geologists. In this field, however, the crevices are so persistently 
reported by drillers and operators that there seems no reasonable doubt 
of their existence. Further, fragments blown up by torpedoes sometimes 
show a honey-comb structure, the openings having a length of several 
inches. The surface of these cavities indicate that the work has been done 
by solution. The larger crevices have probably been made in the same 
manner by enlarging cracks and joints. The depth of crevices vary 
greatly, usually ranging from a few inches to a foot or two, but occasion- 
ally much larger depths are reported. As will readily be understood 
these openings are much dreaded by drillers; when the crevice is not 
vertical the hole is in danger of becoming crooked, and the tools are liable 
to become fast. 7 
It appears that many of the largest oil and gas wells were secured 
in localities where crevices are numerous. Such wells commonly begin 
with a very heavy flow, and this may be long maintained. There are 
many cases, however, where such wells have been exhausted in a few 
months, the theory being that the crevice has been emptied. Sometimes 
when extra large producers have been secured; a rival company, owning 
an adjacent lease, drills on it with the hope of securing part of the oil or 
gas. If this is not secured when the Trenton rock has been penetrated 
to a depth of perhaps 50 feet, a heavy charge of nitroglycerine is used to 
break into the crevice. It is believed that efforts of this kind have been 
failures more frequently than successes. 
Occasionally oil and gas are found in rocks other than the Trenton. 
On section 51, “Maumee river tract,” a well drilled in the autumn of Igor 
found oil in the Clinton limestone, the production being 3 barrels per 
day in the following July. In fact it is not uncommon to find a small 
quantity of oil and gas in this formation. 
The great shales lying below the Clinton also produce occasionally 
both oil and gas, but as a rule the duration of such is brief. A well in 
Bloom township had an initial production of 300 barrels per day, the 
oil having been secured at a depth of 300 feet in the Cincinnati shales. 
This produced between 4,000 and 5,000 barrels of oil, and then giving 
out, the hole was extended to the Trenton. A well near Waterville found 
oil at the same horizon, the production starting at 125 barrels per day. 
The total yield, however, did not exceed more than 2,000 barrels. 
