56 
Ohio Naturalist. 
[Vol. 1, No. 4 
The depth of the well as shown by the steel line is 1012% feet. 
It was drilled in the Fall of 1896, and was shot with twenty quarts 
of nitro-glycerine. It began flowing thirty barrels per day, but the 
production has diminished until at present it is producing only one 
barrel per day. Below the Berea the Bedford shales are found in 
their normal conditions. 
The Oil Sand. — This is in all cases the Berea. The sand has 
the light gray color so common in this formation in other parts of 
the state. It is moderately fine grained, but there is considerable 
variation in this respect. Usually it is a pure quartz sand, but 
occasionally has thin layers of dark shaly material running through 
it. In thickness it shows considerable variation, but never disap- 
pears in this field. The normal thickness is usually given as twenty 
feet and the maximum reported is eighty feet. This depth was 
found on the Potts farm about one and one-fourth miles northeast 
of Corning, and on the O’Farrell farm about two miles east from the 
same town. In both cases a dark gray shale, probably the Ohio, lay 
below. The Bedford on this theory had been swept away before the 
Berea was deposited. In such abnormal depths the additions always 
appear to be on the bottom, showing that the surface of the under- 
lying Bedford shale was quite uneven. Here, as elsewhere in the 
state, the drill shows the upper surface of the Berea to be uniform. 
It is worthy of note that the production of oil does not vary as the 
thickness of the sand. In fact in this field the great thicknesses are 
generally poor producers. 
The “pay streak” or that containing the oil and gas ranges in 
thickness from 3 to 8 feet, but very few of the wells attain the max- 
imum figure. Tow'ards the margin of the prodctive field the “pay 
streak” thins, and finally disappears. The top of the “pay” usually 
lies from 10 to 15 feet below the surface of the Berea. As a rule the 
“pay” is coarser than other parts of the Berea, and generally the 
coarser the rock the larger the well. Sometimes in the thick part 
of the Berea there are two “pay streaks.” 
The Wells. — The number of wells producing July 1, 1900, ex- 
ceeded 600. About 100 dry holes have been drilled and about an 
equal number of wells have been abandoned, so that 800 is a fair ap- 
proximation of the total number of wells drilled in the field. As a 
rule a well has been put down for each 8 to 10 acres of surface terri- 
tory. 
The wells have been cased through the salt sand, a depth of 555 
feet in the valley at Corning. The casing has almost invariably been 
inches, inside measurement. The rocks comprising the underly- 
ing 160-180 feet, and terminating with the “Little Salt Sand” have fur- 
nished some water which has been disasterous to the wells. It re- 
duced the gas pressure, thus necessitating pumping the wells earlier 
than otherwise would have been required, and perhaps prematurely 
