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 disappears 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 underlying 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 maximum figure. Towards the margin of the productive 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, exceeded 600. About 100 dry holes have been drilled and about an equal number of wells have been abandoned, so that 800 is a fair approximation 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 territory. 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 5⅝ inches, inside measurement. The rocks comprising the underlying 160-180 feet, and terminating with the “Little Salt Sand” have furnished some water which has been disastrous to the wells. It reduced the gas pressure, thus necessitating pumping the wells earlier than otherwise would have been required, and perhaps prematurely destroying the life of the well. Had the wells been cased through the “Little Salt Sand” time and money would have been saved, and the production of the field would have been larger.