Page:Popular Science Monthly Volume 9.djvu/165

 Rh, and has been found in considerable quantity in West Virginia, Ohio, Kentucky, and Tennessee. It has also been found, but in small quantities, in New York State, near Chicago, in Michigan, Indiana, Colorado, and California. The oil of Southern California comes from Tertiary shales, and is said to contain no paraffine.

The Upper Oil-Region of Pennsylvania begins in the vicinity of Tidioute, on the Alleghany, in Warren County, and runs southwest to Titusville, thence nearly south, along Oil Creek, into Venango County to Oil City, and thence southwest to Franklin. East Sandy, on East Sandy Creek, is at the extreme southeast edge of this field, and forms the only connecting link between the upper and lower oil-fields of the State. The principal points in this upper region are Tidioute, Triumph, and Economy, in the Tidioute District; West Hickory, New London; the Titusville District, including the Drake well; Church Run, Pit-Hole, Shamburg, Petroleum Centre, Rouseville (between these two places were the Blood well, of 1,000 barrels daily, and the Phillips well, which once flowed 3,940 barrels in twenty-four hours, and has produced over 500,000 barrels), Oil City, Sage Run, and Franklin. The Valley of Oil Creek, within a length of twenty miles, produced over $110,000,000 worth of oil, from an actual area of less than three square miles.

The Lower Oil Belt begins at Triangle City, Beaver Creek, Clarion County, and runs southwest twenty-one miles to St. Joe, in Butler County, and is the greatest producing area so far found (H. E. Wrigley, op. cit.). In 1866 rock with some oil was struck at Brady's Bend at a depth of 1,100 feet, giving rise to further investigation of the river above, which resulted in the discovery of a sand-rock of 57 feet thickness, at a depth of 960 feet, on the Alleghany River at Parker's Landing. A number of wells that had been supposed failures were afterward drilled to the proper depth, with great results.

The oil-bearing rock of Pennsylvania is a sand-rock, of which different strata are struck at different depths.

The operators speak of these as the first sand, second sand, and so on. After going through loose soil and a shale or slate-rock, the first sand is struck generally near the surface in the upper oil-regions (at a depth of 71 feet in the case of the first well sunk, the Drake well); 100 to 200 feet below this is the second sand; at 300 to 400 feet more the third sand, and then a fourth and fifth sand at intervals of about 150 feet. These sand-rocks are generally light-colored, and are separated by slate and other dark sand-rocks.

The heavy oil of Franklin comes from a sand-rock 260 feet deep, and from 50 to 80 feet in thickness. The rower sand-rocks are said to produce very bright, pure oils. Only 39.5 square miles of the 3,115 miles of the oil-region of Pennsylvania are actually productive.

The West Virginia oil-wells occur along an anticlinal extending from the borders of Southern Ohio through Wood, Wirt, and Ritchie