American practice in this field is immensely in advance of all other, and in fact this business has become with us almost a distinct branch of mechanical engineering. Years of experience are required to gain a full knowledge of it, and those who attain such knowledge command the consideration and pay of other mechanical experts. Rock-boring in this country, or at least the drilling that has led directly to our present practice, was begun in 1806, in the Kanawha Valley, by the Ruffner brothers, who were searching for salt water strong enough and abundant enough to warrant the establishment of salt furnaces at the points where the drilling was done. Their search was successful, and well-drilling has gone on uninterruptedly from that date to the present time in this and in adjoining regions, and it is here that all of the most distinctive and characteristic features of the American system of deep drilling have originated. To the Kanawha Valley we owe the "casing" of wells, whereby surface waters are excluded, the "seed-bag," or packer, by means of which the contents of deep-lying strata are separated from the contents of all overlying strata at pleasure, the "jars" or "slips" which make one of the most indispensable elements of the driller's outfit. An admirable account of the successive steps in the development of well-drilling tools and machinery was furnished by Dr. John P. Hale, of Charleston, West Virginia, for Professor M. P. Maury's centennial account of the resources of West Virginia. This account is copied in Professor Peckham's report on Petroleum, which appears in volume X of the United States Census Reports, Washington, D. C., 1884. Another account of almost equal value is to be found in Dr. S. P. Hildreth's "Observations on the Bituminous Coal Deposits of the Valley of the Ohio and the accompanying Rock Strata," etc., which appeared in the American Journal of Science in 1836. It was this Kanawha Valley system of rock-drilling, improved and expanded by fifty years of experience, mainly in the salt wells of the Ohio Valley, that the oil-well-driller found at his command when the petroleum excitement of 1858 broke out in western Pennsylvania. Under the stimulus of this extraordinary demand, the efficiency of the drilling tools has been greatly increased and the character of the driller's outfit greatly improved since this date, but only one important addition has been made to the system itself, by all of the extended experience of the oil regions. The addition referred to consists in the use of torpedoes, lowered into the wells to the depth of the oil or gas-producing stratum and there exploded. By this means the production of deep wells is often greatly increased. In many districts a well is not considered finished until it is torpedoed or "shot," to use the driller's term. These new facilities for underground exploration have been very widely used within the last few years, and from them we have learned a great number of geological facts-some of them of extreme interest and importance. Among other things, we have learned that petroleum and inflammable gas are almost universally distributed throughout the stratified rocks of this part of the world. The drill very seldom descends for even a few hundred feet through any portion of our various rock-formations without disclosing their presence. To find them "in paying quantity" is, of course, the rare exception, but small amounts of one or both are rarely if ever missed, whether the drill descends through sandstone, shale or limestone of Carboniferous, Sub-carboniferous, Devonian, Upper Silurian or Lower Silurian age, or even through heavy beds of bowlder clay. It thus appears that a review of the several sources of petroleum and gas in the Ohio geological scale, for example, would necessitate a review of this scale itself. In fact, no description of the occurrence of these substances in our strata can be made fully intelligible unless the geological order is held firmly and distinctly in mind. A brief review of the scale of the state will accordingly be furnished at this point. A. THE GEOLOGICAL SCALE OF OHIO. The geological scale of Ohio comprises strata of Lower Silurian, Upper Silurian, Devonian, Sub-carboniferous and Carboniferous age, and also a series of glacial deposits. The principal divisions are shown in the following table. The thickness that is assigned to each of the elements is not necessarily the average thickness of the various exposures. In some cases, the general measure is given; in others, it is counted better to indicate the thickness of some of the more characteristic exposures. In the text, the limits of each formation will be more definitely given : 12. Sub-carboniferous limestone, Maxville, Newtonville, etc Shale, 150-450 11. Waverly Group 11c Berea Shale, 20-50 500 to 800' 11b Berea Grit, 3 to 160 11a Bedford Shale, 50-150 10c Cleveland Shale 10. Ohio Shale 10b Erie Shale........250 to 3,000 ft......... 9. 6. Niagara Group Hamilton Shale (Olentangy Shale?). 8. Devonian Limestone, Upper Helderberg or Corniferous, 7. Lower Helderberg limestone or Waterlime, including 6d Hillsboro' sandstone 6c Guelph or Cedarville limestone, 6b Niagara limestone 6a Niagara Shale, including Dayton 5. Clinton Group, in outcrop, 20 to 75 ft.; under cover, 75 ............ 75 ......... 4. Medina Shale, in outcrop, 25'; under cover, 50 to 150... 3. Hudson River Group, 300′ to 750′ 2. Utica Shale, not seen in outcrop, but 300 ft. thick un- 300 500 30 1. Trenton limestone, seen only in Pt. Pleasant quarries... The geological order above described is further represented in the accompanying diagram, figure I. A brief review of each of these divisions will next be made. 1. THE TRENTON LIMESTONE. The Trenton limestone is one of the most important of the older formations of the continent. It is the first wide-spread limestone of the general scale. It extends from New England to the Rocky Mountains, and from the islands north of Hudson's Bay to the southern extremity of the Alleghany Mountains in Alabama and Tennessee. Throughout this vast region it is found exposed in innumerable outcrops. It gives rise as it decays to limestone soils which are sometimes of remarkable fertility, as for example, those of the famous Blue Grass region of central Kentucky, which are derived from it. It is worked for building stone in hundreds of quarries, and it is also burned into lime and broken into road metal on a large scale throughout the regions where it occurs. But wide-spread as are its exposures in outcrop, it has a still wider extension under cover. It is known to make the floor of entire states in which it does not reach the surface at a single point. It takes its name from a picturesque and well-known locality in Trenton township, Oneida county, New York. The West Canada Creek makes a rapid descent in this township from the Adirondack uplands to the Mohawk Valley, falling 300 feet in two miles by a series of cascades. These cascades have long been known as Trenton Falls, and the limestone which forms them was appropriately named by the New York geologists, the Trenton limestone. The formation, as seen at the original Devonian. |