Historical Collections of Ohio

By Henry Howe

Vol. I

©1888

 

THE GEOGRAPHY AND GEOLOGY OF OHIO.—Continued

By EDWARD ORTON, STATE GEOLOGIST.

 

 

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It is much richer in the fossils of the Subcarbonifemus than any of the other members. In composition it is varied and striking, one of its elements being a massive conglomerate not less than 200 feet in its largest sections, which extends in unbroken outcrop through at least a dozen counties of Ohio. No good reason can be found for dividing the Waverly series at all if a member like this is to be left without a name, or is to be merged with an unlike and incongruous division from which it is as sharply differentiated as any one stratum of Ohio is from any other.

 

The real, though not the formal, separation of this group from the underlying shale is due to the late Prof. E. B. Andrews, and constitutes one of his most important contributions to our knowledge of Ohio geology. He was the first to show that the great conglomerate of Hocking, Fairfield, and Licking counties is Subearboniferous in age and he further called attention to a highly fossiliferous, fine-grained sandstone overlying the conglomerate, to which he gave the name of Logan sandstone, from its occurrence at Logan, Hocking county. Up to this time this conglomerate had been universally counted as the Coal Measure conglomerate. Read made known the existence of a heavy body of shale, which he called Olive shales, overlying the conglomerate and replacing the Logan sandstone in Knox, Holmes, and Richland counties.

 

As both conglomerate and sandstone have their typical outcrops at Logan, no better name can be found for the formation which must include conglomerate, sandstone, and shale, than that here adopted, viz., Logan group.

 

The maximum thickness of the Logan group is not less than 400 feet. Its average thickness is perhaps 200 feet.

 

A typical or representative section of this group is scarcely possible, but the most characteristic and persistent part of the series is the conglomerate that is found at the bottom. At all events, coarse rock, if not always technically conglomerate, is generally found here. Pebbles do not make a conspicuous part of the rock when it takes a conglomeritic phase in all cases. The most characteristic feature of the pebbles is their small and uniform size. The larger pebbles are generally flat.

 

Its best developments are in Hocking, Fairfield, Ross, Vinton, Licking, Knox, and Wayne counties, which constitute the northwestern are of the sea-boundary of Ohio in Subcarboniferous time. South of Ross county it loses most of its pebbles, and south of the Ohio it becomes the knobstone of Kentucky. In Northeastern Ohio the Logan group is also destitute of pebbles, and perhaps the conglomerate element proper does not appear here at all.

 

Diverse as these elements are, they are blended and interlocked in the Logan group, leaving it in stratigraphy and fossils a well-defined and easily followed series throughout all parts of the territory in which it is due, except in possibly a small area in Northern Ohio, as already noted, and even here there is no difficulty in recognizing the presence of this series. The several elements are, however, of smaller volume than elsewhere.

 

Under cover, throughout Southeastern Ohio, the series is in the highest degree persistent and regular; much more uniform, indeed, than in its outcrops. It consists of 200 feet or more of prevailingly coarse rock, almost everywhere pebbly in spots, but interrupted with sheets of shale, yellowish and reddish colors being the characteristic ones. It has considerable interest in connection with gas, oil, and salt-water in Ohio being the reservoir of the brines of the Hocking and Muskingum valleys, and furnishing in the latter large supplies of gas in the early days of salt manufacture in the State.

 

12. THE SUBCARBONIFEROUS LIMESTONE.

 

This element is of comparatively small account as a surface formation in Ohio, but it gathers strength to the southeastward of its outcrops, and is shown in many well records as a stratum fifty or more feet in thickness. It was recognized as a member of our geological column by the geologists of the first survey, but Andrews was the first to assign it to its proper place and to show its true equivalence. He named it the Maxville limestone, from a locality in southwestern Perry county.

 

The limestone, in its best development, is a fairly pure, very fine-grained, sparingly fossiliferous rock. It breaks with a choidal fracture. In fineness and homogeneity of grain it approaches lithographic atone, and has been tested in the small way for this special use. It is seldom even and regular in its bedding. Its color is light-drab or brown, and often it is a beautiful building stone, though somewhat expensive to work. The fire-clay found at this horizon in Southern Ohio is one of the most valuable deposits of this sort in our entire scale. The limestone is found in outcrop in Scioto, Jackson, Hocking, Perry, and Muskingum counties. It is reported in the well records of Steubenville, Brilliant, Macksburg, and at several other, points in the Ohio valley.

 

13-17. THE CONGLOMERATE AND THE COAL MEASURES.

 

These two divisions can be properly considered under one head, inasmuch as they have common sources of value. Their aggregate thickness is not less than 1,500 feet, and they cover more than 10,000 miles of the surface of Ohio. The beds of coal, iron are fire-clay, limestone, and cement rock that they contain render insignificant, the contributions made by all other formations to the mineral wealth of the State. In the combined section of the conglomerate and lower coal measures, which contains from 500 to 800 feet of strata, the following named coal seams, are found:

 

 

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A few sporadic seams are omitted from the list.

 

All of these seams belong to the bituminous division. Thus far they are chiefly worked in level-free mines and very little coal is taken from seams less than three feet in thickness. The average thickness in the important fields is five feet and the maximum a small area of a single district) is thirteen feet. All of the seams enumerated are worked, but they have very unequal values. The Middle Kittanning seam is by far the first. It is known as the Nelsonville coal, the Hocking Valley coal, the Sheridan coal, the Coshocton coal, the Osnaburg coal, etc. The Upper Freeport seam ranks nest in value. It is mined at Salineville, Dell Roy, Cambridge and in the Sunday Creek and Monday Creek valleys on a large scale.

 

In proportion to its area the Sharon coal is the most valuable of the entire series. It is the standard for comparison of all the open-burning coals of the Allegheny coal-field. Both this seam and the Middle Kittanning seam are wed in the raw state for the manufacture of iron a fact which sufficiently attests their purity and general excellence.

 

In the remaining divisions of the coal measures there are ten or more seams that are sometimes of workable thickness, but with one notable exception they are less steady and reliable than those of the lower measures. The exception is the Pittsburg coal, which is, all things considered, the most important seam of the entire coal-field to which it belongs. It is especially valued for the manufacture of gas and the production of steam. Its northern outcrop passes through nine counties with an approximate length of 175 miles, the sinuosities not being counted. The area commonly assigned to it in Ohio exceeds 3,000 square miles, but the seam has been proved for only a small part of the area claimed. Ohio is deficient in coking coals of the highest quality. Its beat coals are open-burning.

 

Ohio ranks second in the production of bituminious coal in the United States at the present time, being inferior to Pennsylvania alone in this respect. The output for 1887 is given by the State mine inspector as 10,301,708 tons of 2,000 pounds.

 

The coal measures of Ohio are important sources of iron ore and fire-clay as well as of coal, as is true of coal measures generally.

 

Iron ore is mined in the Ohio coal-fields at a dozen or more horizons, but there are three or four that monopolize most of the interest and importance. The ferriferous limestone ore of the Hanging Rock district is a thin but valuable seam. The iron manufactured from it has unusual strength and excellence and is applied to the highest uses, such as the manufacture of car-wheels and machine-castings. The ore seam does not average more than twelve inches in thickness. The thickest beds of ore in the State are the blackband deposits of Tuscarawas, Stark and Carroll counties. A maximum of twenty feet is here attained. Blackband of good quality and in large amounts is also found in a number of other counties. The block ores of the Mercer horizon rank nest in value among the sources of iron in the State. The total amount mined annually exceeds 500,000 tons.

 

In iron and steel manufacture and working Ohio ranks second only to Pennsylvania, the value of the annual production being counted $35,000,000.

 

The clays of the coal measures are the basis of a large and rapidly growing manufacture of fire-brick, stoneware, earthenware sewer pipes, fire-proofing, paving blocks and paving brick. In all these manufactures Ohio stands far in advance of any other State.

 

The salt manufacture of the State has been large, but is now a depressed and decaying industry. The annual yield is now less than 500,000 barrels. In connection with its salt production Ohio furnishes a notable percentage of all the bromine made in the world. The figures have been as high as 50 per cent.  The brine of the Tuscarawas valley is richer in bromine than any other known in the world. It yields about three-fourths of a pound of bromine to every barrel of salt.

 

In the total value of its quarry products Ohio ranks easily first among the States of the Union. The census of 1880 credits the State with an annual value of more than $2,500,000 in this division. The output of Ohio quarries is rapidly increasing. Its sandstones, especially the products of the great stratum already described as the Berea Grit; hold the first place among the building stones of this class in the country at large. In durability, strength, attractive colors and in general adaptation to architectural effects they leave little to be desired. Red sandstones, both dark and light, that are susceptible of excellent use in the ornamental way, are also abundant in the Subcarboniferous deposits of our scale. The grindstone grits of the State, taken from the several horizons already named, furnish by far the largest contribution to this important use that is made by any single State.

 

The petroleum and gas that our rocks contain and upon which such extreme value is coming to be placed will be discussed at better advantage on a subsequent page.

 

18. THE GLACIAL DRIFT.

 

 

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vegetable matter, the remains of coniferous forests that occupied the country before the advent of the drift, or at some interglacial stage of its duration. Peat bogs are sometimes found buried in like manner m or under the bowlder clay. The deposits of latest age in this great series consist of stratified clays, sands and gravels. The maximum thickness of drift beds that has thus far been found in the State is 530 feet. This measurement was obtained from Saint Paris, Champaign county. Depths of 300 and 400 feet are no longer unusual. The average thickness of these accumulations in Northwestern Ohio exceeds 100 feet. They exercise a controlling influence upon the relief, drainage, soils and water supply of the regions which they occupy. They have filled the valleys of earlier drainage systems and in many cases have obliterated all traces of their existence, thus restoring to large portions of the State the uniformly level surface which prevailed in them when they were first elevated above the waters of the ocean.

 

The bowlder clay or till is filled with bowlders of northern origin, derived from the highlands of Canada and intervening districts. Some of them contain 2,000 cubic feet above ground. They can in many cases be referred to particular localities and sometimes to particular ledges from a score of miles to 400 miles distant.

 

The stratified drift contains vast accumulations of sand, gravel and clay, all of great economic value. Brick clays of good quality are everywhere accessible. These stratified beds constitute a natural filter for surface water to a great extent. The rainfall descends slowly through them until the impervious bowlder clay is reached. The depth of the surface of this last named deposit, in large areas of the State determines the depth of the ordinary wells of these areas. Sometimes, however, a water supply is derived from seams of sand and gravel within the bowlder clay or immediately below it. Such a supply is to quite an extent protected from surface impurities.

 

The terminal moraine that marks the boundary of the glacial deposits is fairly distinct throughout the State. Soils and vegetation unite to emphasize it, as well as special accumulations. It passes through the counties of Columbiana, Stark, Wayne, Richland, Holmes, Licking, Fairfield, Ross, Highland, Adams and Brown, crossing the Ohio river into Kentucky from the latter county but returning to the north side of the river again in Southeastern Indiana. As a result of this temporary obstruction of this great water way it has been pointed out that the waters of the Ohio must have been dammed back so as to form a large lake, including the valley proper and its tributaries as far at least as Pittsburg. The barrier appears to have given way in such a manner as to reduce once and again the level of the intercepted waters abruptly. Such a mode of retreat, at least, would explain the successive terraces that border the main streams at the present time.

 

II. GEOLOGICAL STRUCTURE.

 

The geological scale of the State has now been briefly treated. An equally brief account must be added of its structure. By this term is meant the present arrangement or disposition of the strata as effected by all the movements of the earth's crust in which they have had a part, and by which they may have been bent into arches or troughs or left in terrace-like monoclines.

 

The geological structure of Ohio is as simple as that of almost any other 40,000 square miles of the earth's surface. All of its strata except a small portion of the coal measures were deposited in the waters of an ancient arm of the sea, of which the present Gulf of Mexico is the dwarfed and diminished remnant and representative.Its most fossiliferous limestones, as the Corniferous, for example, stand for clear waters of tropical warmth. Its conglomerates and sandstones required strong currents for their transportation from distant shores. Its shales must have been deposited in seas of at least moderate depth, large areas of which, as well as all of the shores, were covered with sargasso-like masses of sea-weed.

 

These strata seem to have been deposited on a fairly regular and level floor, and they have never been subjected to very great disturbance; that is, they have nowhere been raised into mountains nor depressed into deep valleys, but still they have been warped and distorted to some extent in the course of their long history.

 

The Cincinnati Anticlinal.

 

As soon as the geology of the Mississippi valley began to be studied, it became apparent that there had been in early time an extensive uplift of the older rocks in the central parts of Tennessee and Kentucky and in Southwestern Ohio, which had exerted a profound influence on all the subsequent growth of the regions traversed by received adjacent thereto. This uplift has received several designations, but the name given to it by Newberry, viz., the Cincinnati anticlinal, will here be adopted, inasmuch as this geologist has furnished by far the most careful and connected account that has yet been given of it.

 

It is to be recognized, however, that this structural feature has in it little or nothing of the character of an anticlinal or arch, as these terms are commonly understood. There is no roof-shaped arrangement of the strata whatever, but they are spread out in a nearly level tract, 100 miles or more in breadth. The slopes within the tract are very light, and are quite uniform in direction, and the boundaries of the tract are well defined, as a rule.

 

 

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the State we have obtained soundings to this limestone floor so extensive that we are already able to restore approximately its to topography.

 

This underground disposition of the Trenton limestone becomes very significant in connection with the Cincinnati uplift. In fact it is the Cincinnati uplift; and the study of the facts pertaining to it will be found to throw more light on this earliest and most important structural feature of the State than can be obtained from any and from all other sources. The results are altogether unexpected.

 

It appears that in Lower Silurian time a low fold, extending in a general northeast direction, entered Ohio from the southward and continued its advance across the State during immense periods of time. It has heretofore been believed that the fold as it extended across the State held its original northeasterly direction, but it now becomes evident that in its earlier stages in Ohio it advanced to the northwest instead, extending into Northern Central Indiana, so far as its main body was concerned. From this point an off shoot of smaller area was directed into Ohio, the boundaries of which are found to be very irregular, and in connection with which some surprising within Ohio geology have come to light. With these same facts extraordinary economic interest has been found to be associated.

 

The easterly or southeasterly dip of the rocks that begins at the margin of the tract, now described as the Cincinnati axis, continues through the subsequent history of the State, and constitutes the most important physical feature of its geology. All of the Subcarboniferous and Coal Measure strata, in particular, are affected by it. The southerly element of it gradually increases as we pass to Northeastern Ohio, and it is probable that the dip becomes due south at some points in this portion of the State. Beyond the limits of Ohio, in Pennsylvania and West Virginia, the corresponding strata descend sharply toward the westward. These facts considered together mark out the limits of the arm of the sea in which, and around which, the northern extension of the Appalachian coal-field was built up, the Cincinnati axis forming its western boundary. These uniform and continuous southeasterly dips can be explained by the steady growth of the land to the westward, after the fashion already described. The dip is at right angles to the constantly advancing border of the sea. It seldom exceeds thirty feet to the mile, or but little more than half of one degree, in the large way, but it is alternately sharpened and reduced, so that for short distances a much greater fall, or much less, may be found.

 

The facts of our present topography seem to point to an original equality of elevation of those portions of the State that were successively brought under this uplifting force. The western outliers of all of the formations are, at the present time at least, at approximately the same elevation above the sea.

 

The statements already made as to the exceeding regularity of the geological structure of Ohio need no qualification, but this regularity of the State, as a whole, is not inconsistent with the existence of a few minor folds and arches, distributed especially through the eastern half of our territory.

 

In the southeastern quarter are a few anticlinal arches, all of which, however, are very gentle and low, and none of which can be traced for many miles in the direction in which they extend. They involve all of the strata that belong in the district in which they are found. A modification of the arch resulting in a terrace-like arrangement of the strata is one of the most important phases of the structure in this portion of the State. Among the arches all of which are very feeble, the Fredericktown and Cadiz arches, which are probably one and the same, maybe named, and also the Cambridge anticline. The Macksburg oil field affords an excellent example of the terrace structure.

 

To sum up the statements now made, we know but comparatively few arches in Ohio and these few are moderate in slope and small in height.  Fuller knowledge of our geology will doubtless give us a larger number of these low folds, but there is little probability that any sharp and well-defined anticlinals have altogether escaped notice. Those that .remain to be discovered will agree with those already known, in breaking up the monotony of our series by the suspension or occasional reversal of the prevailing dip and in requiring close and accurate measurements for their detection.

 

By untrained observers, the water-sheds of our drainage channels are often mistaken for anticlinals. If anticlinals traverse the series where these identifications are made, they may well serve to divide the drainage systems from each other, but such "divides" do not by any means require these structural accidents as the conditions on which they depend. Anticlinals must be demonstrated, not inferred.

 

There are but few districts known in Ohio in which disturbances are to be found that fairly deserve the name of faults. In the northeast corner of Adams county, and in adjacent territory, there are a number of square miles throughout which the strata are really dislocated. The Berea grit is found in contact with the Niagara shale in some instances the throw of such faults must be at least 400 feet. Faults of this character in Ohio geology are as unusual and unexpected as trap dykes in Northern Kentucky, the latter of which have been recently reported by Crandall.

 

III. PETROLEUM AND NATURAL GAS.

 

 

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large scale is of comparatively recent date. It was begun in Pittsburg and in the region around it a dozen years since, but it is only within the last six years that it has made a deep impression upon the country at large.

 

The cheapness of the new fuel, the economy resulting from several different factors in its use, the improvement of product in a number of lines of manufacture, all combine to give a decided advantage to the centres that have been fortunate enough to secure it, and to make competition seem almost hopeless to the towns that are without it.

 

In consequence, an earnest and eager search for natural gas has been begun throughout entire States, and vast, amounts of money have been used in carrying forward these explorations. Next to Western Pennsylvania Northwestern Ohio has scored the most signal success and, following the experience of Ohio, Eastern Indiana has also found one of the most valuable fields of the country.

 

The production of petroleum and gas in Ohio will be briefly described in this section, but, preceding this description, a few statements will be made as to the theories of origin and accumulation of these substances which seem best supported.

 

ORIGIN OF PETROLEUM AND GAS

 

It is not necessary to consider the origin of natural gas and petroleum separately. They have a common history. They are produced from the same sources, accumulated by similar agencies, and stored in the same reservoirs. In order of formation, petroleum is probably first. It is the more complex in composition and thus nearer to the organic world from which it is derived. Gas is the same substance on the downward road to the simplicity of inorganic compounds. No process is known by which gas is built up into oil, but the breaking up of petroleum into gaseous products is seen to be constantly going forward in nature, and it is also effected in the large way artificially.

 

Petroleum never exists free from gas, but it is sometimes asserted that gas is found that has no connection with petroleum. This claim is probably a mistaken one, and if the dryest gas could be followed throughout its underground reservoirs, it is altogether probable that accumulations of oil would be found along the line in every case. There is no horizon known that produces either substance to the entire exclusion of the other.

 

As already implied, petroleum and gas are derived from the organic world. Both vegetable and animal substances have contributed to the supplies, and these separate sources give different characters to their products, as will be presently shown: There are certain other theories in regard to the origin of petroleum, it is true, which have been advanced by eminent chemists, but which do not match at all well with the geological facts involved. These last-named theories refer petroleum to peculiar decompositions and recompositions, chiefly of water and carbonic acid, which are supposed to be carried on at considerable depths in the earth, where these substances are brought into contact with metallic iron or with the metallic bases of the alkalies at high temperatures. Never were more artificial or unverifiable theories presented for the explanation of natural phenomena, and it is surprising that they should have obtained any currency whatever. Something might be said for them, perhaps, if we had no ether possible way of accounting for the facts to which they refer, but when they are compared with the theories of organic origin they have no standing-ground. The truth is, we are constantly manufacturing from animal and vegetable substances in the large way; both gas and oil that are fairly comparable m both chemical and physical characteristics with the natural products. Further, we find vegetable substances passing by natural processes into petroleum and allied compounds, so that there is no need whatever to invent a strained and fantastic theory based on remote chemical possibilities, in order to cover the ground. These chemical theories teach that the process of oil and gas formation is a continuous one, and no reason is apparent why stocks may not be maintained from such a source even when they are drawn upon. Perhaps it is this feature that has recommended these theories more than any other. Any doctrine that gives us unwasting supplies of force is sure to be popular as long as it can find the semblance of justification, as witness the hold that the claims for perpetual motion have on the public mind.

 

The petroleum and gas of shales and sandstones, are in the main derived from vegetable matter, and as the principal stocks are found in sandstones, vegetable matter may be said to be the chief source. The oil and gas of limestones are presumably derived from animal matter, inasmuch as the limestones themselves are known to be, in the main, a product of animal life.

 

The vegetation principally employed in this production is of the lower kinds, sea weeds and other allied groups being altogether the most conspicuous elements. The animal life represented in limestone oil and gas is also of the lower groups. Plants may have been associated also with animal matter in the formation of limestone oil, to some extent.

 

HOW WAS PETROLEUM FORMED?

 

To the question, How were these bodies formed out of organic matter?  there are various answers.

 

They are most commonly referred to the agency of distillation. Destructive distillation consists in the decomposition of animal or vegetable substances at high temperatures in the absence of air. Gaseous and semi-liquid products are evolved, and a coke or carbon residue remains behind. The "high temperatures" in the definition given above must be understood to cover a considerable range, the lower limit of which may not exceed 400 or, 500 degrees F.

 

 

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not the products of destructive distillation. If shales, sandstones, or limestones holding large quantities of organic matter, as they often do; and buried at a considerable depth, should be subjected to volcanic heat in any way, there is no reason to doubt that petroleum and gas would result from this action. Without question, there are such cases in volcanic districts, but the regions of great petroleum production are remarkably free from all igneous intrusions, and from all signs of excessive or abnormal temperatures. All claims for an igneous origin of these substances are emphatically negatived by the condition of the rocks that contain them.

 

There is a statement of the distillation theory that has attained quite wide acceptance, which needs to be mentioned here. It is to the effect that these substances, oil and gas, have resulted from what is called "spontaneous distillation at low temperatures," and, by low temperatures, ordinary temperatures are meant. It does not, however, appear on what facts in nature or upon what artificial processes this claim is based. Destructive distillation is the only process known to science under the name of distillation, which can account for the origin of oil or gas, and this does not go on at ordinary or low temperatures. A process that goes on at ordinary temperatures is certainly not destructive distillation. It maybe chemical decomposition, but this process has a name and place of its own, and does not need to be masked under a new and misleading designation, such as spontaneous distillation. No help can come to us; therefore, from the adoption of the spontaneous distillation theory.

 

It seems more probable that these substances result from the primary chemical decomposition of organic substances buried with the forming rocks, and that they are retained as petroleum in the rocks from the date of their formation. It is true that our knowledge of these processes is inadequate, but there are many facts on record that go to show that petroleum formation is not a lost art of nature but that the work still goes on under favorable conditions. It is very likely true that, as in coal formation, the conditions most favorable for large production no longer occur, but enough remains to show the steps by which the work is done.

 

The “spontaneous distillation” theory has probably some apparent support in the fact that must be mentioned here, viz.: that where petroleum is stored in a rock, gas maybe constantly escaping from it, constituting, in part, the surface indications that we hear so much of in oil fields. The Ohio shale, for example, is a formation that yields along its outcrops oil and gas almost everywhere, but  ?? recent origin is needed for either. The oil may be part of a primitive store, slowly escaping to the day, and the gas may be constantly derived from the partial breaking up of the oil that is held in the shales. The term “spontaneous distillation” might, with a little latitude, be applied to this last-named stage, but it has nothing to do with the origin of either substance.

 

While our knowledge of the formation of petroleum is still incomplete and inadequate, the following statements in regard to it are offered as embodying the most probable view:

 

l. Petroleum is derived from vegetable and animal substances that were deposited in or associated with the forming rocks.

 

2. Petroleum is not in any sense a product of destructive distillation, but is the result of a peculiar chemical decomposition by which the organic matter passes at once into this or allied products. It is the result of the primary decomposition of organic matter.

 

3. The organic matter still contained in the rocks can be converted into gas and oil by destructive distillation, but, so far as we know, in no other way. It is not capable of furnishing any new supply of petroleum under normal conditions.

 

4. Petroleum is, in the main, contemporaneous with the rocks that contain it. It was formed at or about the time that these strata were deposited.

 

THE DISTRIBUTION OF PETROLEUM AND GAS.

 

Contrary to a commonly received opinion petroleum and gas are very widely distributed and very abundant substances. The drill can scarcely descend for even a few hundred feet at any point in Ohio, without showing the presence of one or both of them. The rocks of the State series can be roughly divided into three great groups—limestones, sandstones and shales. Petroleum is found abundantly in each of these groups. The percentage is small, but the aggregate is large. It is equally, or at least generally diffused throughout certain strata, while in others it is confined to particular portions or beds. An example of the first case is found in the Ohio shale. The Ohio Shale, Cleveland—Erie—Huron, of earlier reports, consists of a series of homogeneous, fine-grained deposits, black, blue and gray in color, 300 feet thick on their western outcrop in Central Ohio, but more than 1,800 feet thick under cover in Eastern Ohio. This entire formation is petroliferous, as is proved by an examination of drillings that represent the whole section. The black bands are probably most heavily charged.  The chemist of the survey, Professor N. W. Lord, finds two-tenths of one percent of petroleum, as such, present in these bands, and is certain from the nature of the processes that he was obliged to employ that the entire amount is not reported. But, estimating the percentage to be but one-tenth of one per cent in place of two-tenths, and calculating the thickness of the shale at its minimum, viz., 300 feet, we find the total stock of petroleum held in the shale to be 1,560,000 bbls. to the square mile, or nearly twice as large amount as has; ever been obtained from any square mile of the Pennsylvania fields.

 

 

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lime, or Lower Helderberg limestone, is probably the most heavily and persistently charged with petroleum. Drillings taken from this stratum, at a depth of 400 to 500 feet below the surface in the trial-well lately sunk at Columbus, are found by Professor Lord to have the same amount of free petroleum that the black shale contains, viz., two-tenths of one per cent. The limestone also has the same thickness that is assigned to the shale on its outcrop, viz. 300 feet. The figures, therefore, duplicated those already given. The total amount of oil from these two sources exceeds 3,000,000 bbls. to the square mile.

 

All the other great limestones of our series carry petroleum, at least in certain beds. The Clinton limestone is often an oil-bearing rock, and the show of its outcrop has led to the sinking of a number of wells in search of oil, in past years. The Niagara limestone is highly bituminous in places. Asphaltic grains, films and masses constitute as much as 4 or 5 per cent of its substance at several points in the State. The Corniferous limestone is also distinctly bituminous in some of its beds. The limestones of the Cincinnati group also carry a determinable amount of petroleum.

 

As for sandstones, all know that it is in them that the main stocks of petroleum have thus far been found, but there is good reason to believe that these stocks are not native in the sandstones, but have been acquired by them subsequent to their formation. This point will be considered further, under another head.

 

MODES OF ACCUMULATION OF PETROLEUM AND GAS.

 

In the accumulation of petroleum, two stages are to be noted, viz.: a primary and a secondary stage. The first is concerned with the retention of petroleum in the rocks, and might have been with equal propriety treated under the preceding head. The second stage is concerned with the origin and maintenance of the great stocks of oil and high-pressure gas, in which all the value attached to these substances lies. Both are connected with the composition of the rock aeries in which oil and gas are found, and the latter is also greatly affected by the arrangement and inclinations of the rock masses, or, in other words, by their structure.

 

The primary accumulation of petroleum, or its retention in the rocks in a diffused or distributed state, seems to be connected with the composition of the series to a great degree. The great shale formation of Devonian and Subearboniferous ages that separates the Berea grit from the Devonian limestone, the western edge of which shale formation outcropping in Central Ohio is know as the Ohio shale (Cleveland, Erie, Huron), is unmistakably the source of the greatest accumulations of oil and gas, so far found, in the country. It holds thus far, as decided, a superiority to all other sources, as the Appalachian coal-field does to all other sources of fossil fuel. The accumulation of petroleum in this great shale formation is no accident. It depends on two factors, viz.: the abundance of vegetable matter associated with the shales in their formation, which is attested by the large amount still included in them, and upon the affinity of clay for oil. The last-named point is an important one. Clay has a strong affinity for oil of all sorts, and absorbs it and unites with it whenever the two substances are brought into contact. Professor Joseph Leidy made the interesting observation a number of years since, that the bed of the Schuylkill river in Philadelphia, below the gas works, was covered with an accumulation of the oily matters that are always formed in the process of gas-making. As these substances are lighter than water and float upon its surface naturally, it was at first sight hard to understand how they could have been carried to the river bed, but it was soon learned that the clay of the river water absorbed the oils as they were floating along, and finally sank with them to the river floor. In a similar way we may suppose the primary accumulation of petroleum in the shales to have been in part accomplished. The oil set free by vegetable decomposition around the shores or beneath the waters of a sargasso sea, would be arrested by the fine-grained clay that was floating in the water, and would have sunk with it to the sea floor, forming this homogeneous shale formation that we are now considering. Sand would have no such collecting power.

 

The distribution of petroleum through limestone is not as easily explained, but it may be in part dependent on the presence of the same element, viz., clay. In almost all limestones there is a percentage of clay present, and frequently it rises to a conspicuous amount. Oil is held in both magnesian limestones and in true limestones in Ohio. The magnesian limestones are largely in excess in the aeries of the State, and it so happens that all of the most pertoliferous strata are magnesian in composition, but this fact is probably without significance in this connection.

 

 

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OIL GROUPS.

 

As the experience of the last thirty years has abundantly shown, an oil or gas series always consists of two elements, viz., a porous rock, or reservoir, overlain by a close and fine-grained impervious rock or cover. A third element must always be added to make out the logical series, viz., an underlying or associated source of oil and gas. It is obvious that the last-named element is first in order and in importance, but for reasons already in part, and for others that are not hard to find, practically we have leas to do with it than with the two former elements, It will be borne in mind that the sources of petroleum are well-nigh universal, and also that they have no economic value, and are therefore seldom penetrated by the drill. The search generally terminates in the reservoir. The great sources of the Ohio scale are, as already implied, shales and limestones, both more or less bituminous. These sources have done their work wherever large accumulation is found, and where no accumulations exist the petroleum occurs, as already shown, in large but valueless stocks distributed through the body of the strata.

 

THE RESERVOIR.

 

The reservoirs must be porous rocks. In all of the experience in the great fields of Pennsylvania and New York, the rocks in which the large stocks of oil and gas were found were, without exception, sandstones or conglomerates. To them the driller early gave the name of "oil-sands," and this name is in universal use. The grain and thickness of these sandstones are found to be important factors in their production. Other things being equal, the coarser the grain and the thicker the stratum, the greater is its production found to be. Mr. J. F. Carll, of the Pennsylvania Geological Survey, our highest authority in regard to petroleum production, has shown that an oil-sand can hold one-tenth of its bulk of oil, and he believes that it may contain under pressure as much as one-eighth of its bulk. This would give 1½ inches of oil to every foot of the oil-sand.

 

Taking the most productive portions of the latter in the Venango field to be fifteen feet we find in that district a possible capacity of 9,600,000 barrels per square mile, an amount, it is needless to say, vastly in excess of any production ever known.—"Second Pennsylvania Survey, Oil Regions," III., pp. 252-53.

 

The driller places great reliance on the oil-sand, and learns to draw conclusions and make forecasts from its character more than from any other single element that he encounters.

 

Within the last few years we, have found in Ohio a reservoir of high-pressure gas and large oil-wells, in a rock of altogether different character from the oil-rocks already described. The new oil and gas-rock of Northwestern Ohio is a magnesian limestone or dolomite, of a good degree of purity. It is as porous, apparently, as the sandstones and conglomerates of the Pennsylvania series, this character being due in the limestone to the imperfect interlocking of the dolomite crystals. The dolomite constitutes but a small portion of the Trenton limestone in which it is found. The normal character of this great sheet is that of a true carbonate of lime, but it appears that, in a limited territory, the upper portions of the stratum have been transformed into dolomite. The transformation seldom extends more than a score or two of feet below the surface and is often confined to five or ten feet. Sometimes a cap of true limestone, five or ten feet in thickness, overlies the dolomite, and sometimes the latter occurs in two or more sheets, separated from each other by the normal rock. The Trenton limestone is not itself a porous or reservoir rock in any sense of the word. It is only these replaced beds that have this character.

 

Besides sandstones and limestones, shales also serve to a small extent as receptacles of accumulated oil and gas in Ohio. The character of the containing rock in these cases is not well known. Generally, the gas is of light pressure, but it is a fairly persistent supply that is found in these rocks. The belt of shales along the shore of Lake Erie gives the examples of this sort of accumulation and supply. These shales, where productive of gas, are found to consist of hard and light-colored bands, interstratified with dark bands, the gas appearing to be found when the harder bands are penetrated. The production of oil from these sources is always small, but, as already stated, fair amounts of gas are sometimes derived from them.

 

Petroleum and gas are not the only substances that are found in these reservoirs. Salt-water is almost an invariable accompaniment of both. The oil-rocks are salt-rocks as well, in some parts of their extent. The distribution of these three substances in the same stratum is connected with facts of structure, as will presently be shown. These reservoirs have been described as porous of necessity. The porosity insures a large amount of lateral permeability, a fact of great importance in the distribution of these substances. The reservoir is often common for large areas. All the wells in a field may find the same pressure of gas or oil, even though their production may be very unequal.

 

THE COVER.

 

 

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found to contain, in some portions, accumulations of gas and oil. The stocks maybe too small to be valuable, but the presence of the shale cover seems to insure some concentration in these situations. There are three points in the Ohio series of rocks where such shale covers occur, viz., at the surface of the Trenton limestone, where 800 to 1,000 feet of shales and intercalated beds of limestone of the Medina, Hudson river, and Utica epochs are found, at the surface of the Corniferous limestone, which is covered by 300 to 1,800 feet of the Ohio shale, and, at the surface of the Berea grit, which is overlain by the best cover of the entire aeries, viz., the close-grained and nearly homogeneous Cuyahoga shale, 300 to 500 feet in thickness. Two of these, the first and the last, constitute the two main horizons of oil and gas in Ohio. The third is not notably productive thus far in Ohio, but it is the source of a small supply in other States.

 

The composition of an oil-producing series is thus seen to be essential to its functions. The order already pointed out cannot be departed from, but there must-always be (1) an impervious cover; (2) a porous reservoir; and underneath the reservoir, the source is to be found.

 

STRUCTURE AS AFFECTING OIL AND GAS ACCUMULATION.

 

But this order of arrangement is not enough in itself to insure any large concentration of oil or gas at any particular place. One other factor must be introduced, viz., structure. The strata which constitute the geological scale of the State nowhere lie, for any considerable extent, in horizontal planes. They are all more or less inclined. Sometimes they are bent into low folds or arches, and sometimes, though very rarely there are abrupt descents and fractures. As a rule the dip, or angle of inclination to the horizon, of Ohio rocks is very small. It is better expressed as a fall of so many feet to the mile, than by angular measurements, which very seldom rise to one degree. Both the rate and the direction of the descent are uniform over large areas. The average dip for important portions of the State is between twenty and thirty feet; the direction depends, of course, upon the part of the State which is to be considered.

 

The movements of the strata here referred have exerted a very important influence on the concentration of oil and gas in the reservoirs already described. If one of these sandstone strata; filled with salt-water, oil, and gas, and freely permeable laterally and horizontally for even miles at a time, were to be thrown into a system of low folds, what effect would this movement have upon the contents of the stratum? Would not a separation of gas oil, and water be sure to follow, the gas finding its way to the summits of the arches, and the salt-water sinking to the bottoms of the troughs? Such a result would be in­evitable under the conditions assumed.

 

The summits of the folds are called anticlinals, and the troughs synclinals. The lines of direction of the anticlinals are called their axes. The influence of these facts of structure on gas and oil accumulating has been long recognized, or at least asserted, but there is not full agreement as to the part that it .plays in the great fields among the geologists who have given most study to the subjects.

 

The facts that have come to light in the recent investigations of these subjects in Ohio seem to show the paramount influence of structure upon oil and gas accumulation. In the old fields, and in the new alike, irregularities of dip, involving change of direction, suspension, or unusual increase, have been found connected with, the large production of both oil and gas in every instance where careful examination has been made. The composition of the series involved is identical for many thousand square miles, but so long as uniformity of dip is maintained, there is no valuable accumulation. As soon, however, as this uniformity is broken in upon, the valuable stocks of gas and oil come to light.

 

The "belt lines," in which the practical oil-well driller and operator of the main field puts so much confidence, so far as they stand for facts in nature, are probably structural lines. A map of the various centres of petroleum in the old field shows that they all extend in the northeasterly course which the main structural features of this part of the continent follow. The driller believes fortune to lie in the 45° or 22½ line which leads out in a northeast or southwest direction from each centre of production. Experience Justifies, to a certain extent, his confidence. The productive gas territory upon which Pittsburg now depends is limited to the summits of a few well-marked anticlinals, which all have a northeasterly trend. In regard to the latter, question can scarcely be raised. The predominant influence of structure is obvious. It seems probable that a careful enough system of measurements will show like lines of modified dip to traverse the great oil fields of Pennsylvania and New York.

 

The occurrence of gas and oil in almost all rocks that have a heavy shale cover would seem to result from exchanges affected by gravity. The oil is associated with salt-water in the stratum that contains it. There would be a constant tendency for the oil to reach a higher level at the expense of the water. It ascends through all the substance of the rock until it reaches the impervious roof, where it is gradually concentrated. On the same principle, the separation of the gas from the oil is effected.

 

Some of the points that have been made under this head may be briefly restated, as follows:

 

 

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vania is the main source of the petroleum and gas of these regions. Clay does its work in this regard by reason of its chemical constitution.

 

2. As clay is the main agent in the primary accumulation of petroleum, sand takes a similar place in its secondary accumulation, or its concentration in valuable stocks. It does this by virtue of its physical character. A sandstone is a porous rock. Such sandstones as ire found overlying or imbedded in the great shale formation are sure to become receptacles of oil.

 

3: Clay has another office in this connection to perform, and this office is dependent on its physical character. The sandstone stratum last described would become a receptacle of oil in any case but if roofed with a sufficient thickness of clay shale by which its contents could be sealed and preserved, it would became a reservoir of oil or gas. All of the stocks of the old fields are held in sandstone or conglomerate reservoirs.

 

4. Limestone has been found, more clearly in Ohio, perhaps, than elsewhere, to replace sandstone in oil accumulation. All the phenomena of high-pressure stocks of oil and gas have recently been found in the Trenton limestone of Northern Ohio, but the presence and office of the shale cover are seen to be the same here as in the other fields. The term limestone in this connection is used with due care and precision. It is limestone, not "oil-sand" in the limestone, that contains Findlay gas and Lima oil. Pure magnesian limestone is the driller's "oil-sand" in these fields.

 

5. Widely diffused as are oil and gas in the paleozoia rocks of Ohio and adjacent States, so wide that the distribution of them may, without error, be styled universal, and widely extended as are the series of rooks that afford in their composition and relations the proper conditions for storage, it is still seen that their accumulation in profitable quantity depends on what might be called geological accidents. It is only or mainly along lines of structural disturbance that the great stocks are found.

 

THE ROCK PRESSURE OF GAS.

 

The facts pertaining to the closed pressure of great gas-wells are among the most striking in the whole range of mining enterprise. To be appreciated, a high-pressure gas-well must be seen and heard. The gas issues from it with a velocity twice as great as that of a pullet when it eaves a rifle. Sets of drilling-tools, nearly 100 feet long, and weighing 2,000 pounds, are lifted out of a well 1,000 or 500 feet deep and thrown high into the air. The noise with which the gas escapes is literally deafening exposure to it often resulting in partial loss of hearing on the part of those engaged about the welt.

 

What is it that originates this indescribable force?

 

One answer is, that the rock-pressure is derived from the expansive nature of the gas. Solid or liquid materials in the reservoir are supposed to be converted into gas as water is converted into steam. The resulting gas occupies many times more space than the dies from which it was derived, and in seeking to obtain this space it exerts the pressure which we note.

 

This view has, no doubt, elements of truth in it, even though it fails to furnish a full explanation for the pressure of shale-gas, it may be that no other force is required. But the theory is incapable of verification, and we are not able to advance a great ways beyond the statement of it. Some objections to it will also appear in connection with facts that are presently to be stated. The second explanation that is offered is, without doubt, more generally accepted than any other by those who have begun to think upon the question at all.

 

This theory is to the effect that the weight of the superincumbent rocks is the cause of the high pressure of gas in the reservoirs. In other words, the term rock- pressure is considered to be descriptive of a cause as well as of a fact. That a column of rock, 1,000 or 1,500 feet deep has great weight is obvious. It is assumed that this weight, whatever it is, is available in driving accumulations of gas out of rocks that contain them, whenever communication is opened between the deeply-buried reservoir and the Surface.

 

Is this assumption valid? Can the weight of the overlying rock work in this way? Not unless there is freedom of motion on the part of the constituents of the rock, or, in other words, unless the rock bas, lost its cohesion and is in a crushed state. If the rock retains its solidity, it can exert no more pressure on the gas that is held in the spaces between its grains than the walls of a cavern would exert on a stream of water flowing through it. Professor Lesley has discussed this theory with more elaboration and detail than any other geologist, and has shown its entirely untenable character. (Annual Report Penna. Survey, 1885.)

 

The claim that the Berea grit or the Trenton limestone, where they are, respectively, oil or gas-rocks, exists in a crushed or comminuted state, is negatived by every fact that we can obtain that bears upon the subject. The claim is a preposterous one, but will out this condition the theory fails.

 

 

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in the traps formed by the anticlinals or terraces into which the stratum had been thrown. The amount of pressure would thus depend on the height to which the water column is raised, in case continuous, porosity of the stratum can be assumed. Defects in regard to porosity would abate from the total pressure on the oil or gas.

 

This, in short, is the third and last of the explanations offered of the rock-pressure of natural gas. There seems little reason to doubt that it is along this line that the true explanation is to be found, though it is too early to claim that a full account can now be given of all the facts involved.

 

One of the significant elements in the case is the salt-water the surrounds every oil and gas-field. When the drill descends into this outside territory, salt-water promptly rises in the well to the surface, or to a given depth below the surface. Sometimes, indeed, it overflows. Why does the salt-water rise?

 

What other cause can be suggested than pressure from behind? The rise must be artesian. But just beyond the salt-water, on a slightly higher level of the rock, lies the oil pool. When that is reached Will the drill, the oil flows out from the well. Will not the same cause that we found in active and unmistakable operation in the adjacent salt-water territory explain the flow of the oil from the second well? Is not this also artesian?

 

In like manner, the pressure of the gas that is confined within the highest levels of the same porous rock can be explained, and thus one familiar cause that is demonstrably present in the field is made to account for the varied phenomena presented.

 

With the exhaustion of a gas-field or oil-field, these substances are followed up and replaced by salt-water. This is the common fate of gas and oil wells, the death to which the all seem to be appointed.

 

Certain obvious inferences follow the acceptance of this explanation:

 

1. The supplies of gas and oil are seen to be definitely limited by this theory of rock pressure. If a salt-water column is the propelling force, it is idle to speculate on constantly renewed supplies. The water advances as the gas or oil is withdrawn, and the closing stage of the oil-rock is, as already pointed put, a salt-water rock.

 

2. Other things being equal, the rock-pressure will be greatest in the deepest wells. The deeper the well, the longer the water column.

 

3, Other things being equal, the rock-pressure will be greatest in districts the gas or oil-rock of which rises highest above the sea in its outcrops. The 750 lbs. of rock-pressure in Pennsylvania gas wells, as contrasted with the 400 lbs. pressure of Findlay wells, can be accounted for on this principle.

 

4. The rock-pressure of gas may be continued with unabated force until the end of production is at hand. Maintenance of pressure is no proof of renewal of supply. The last thousand feet will come out of a gas-holder with as much force as the first thou sand feet.

 

5.Where both oil and gas are found in single field, the first sign of approaching failure will be the invasion of the gas-rock by oil, or of the oil-rock by salt-water.

 

SOURCES OF GAS AND OIL IN THE OHIO SCALE.

 

There are known at the present time four utilizable sources of as and oil among the strata that underlie Ohio They are as follows, named in descending order:

 

l. The Berea grit in Eastern Ohio.

2. The Ohio shale in Northern and Central Ohio

3. The Clinton limestone in Sandusky, Wood, Hancock and Fairfield counties.

4. The Trenton limestone in Northwestern Ohio.

 

The Berea grit yields high-pressure gas and large stocks of oil under favorable circumstances, but these circumstances do not often recur. This stratum is doing but very little in supplying to the people of the State either gas or oil at the present time. Outside of Ohio in Western Pennsylvania it is found to be one of the most important repositories of this stored power that has been discovered in that highly favored territory.

 

The Ohio shale as a source of gas has already been briefly characterized in the account of this formation given on a previous page. It yields low-pressure gas in small amount at many places, but can never be made a source of large supply.

 

The two formations next to be named have special interest for us from the fact that their petroliferous character on the large scale was first demonstrated in Ohio. The first of them, indeed, has never been found to be in oil or gas rock elsewhere. It has not yet been proved to be a reservoir of any great value in Ohio, but moderate supplies of gas have been for some time derived from it in Fremont and in adjacent territory of Northern Ohio. In Lancaster, however, in Southern Ohio, the largest promise of the rock has recently been found. Wells drilled to the Clinton limestone, which is reached at a depth of 2,000 feet, have yielded as much as 1,000,000 cubic feet a day when first struck. The initial rock-pressure is high, viz., 700 pounds to the square inch. It is too early to draw safe conclusions as to the value of this discovery. All turns on the life of the wells. On account of their depth the drilling and casing are expensive. A well cannot be completed for less than $3,500 to $4,000. The facts at present in hand seem to betoken a short duration for the supply. A large amount of money is sure to be spent in the new field that the experience of Lancaster has brought to light.

 

It remains to describe in few words the remarkable discovery of gas and oil in the Trenton limestone that was made at Findlay in November, 1884.

 

 

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been full of surprises, both to the practical men in the work and to the geologist who have studied the facts as they have been brought to light, but no previous chapter of the history has been  proved and well-nigh incredible as the discovery and development which are now to be described

 

No fact in this line could be more unexpected than that any notable supplies of petroleum or gas should be furnished by the Trenton limestone, which is widely know as a massive, compact and fossiliferous limestone of Lower Silurain age and of wide extent, constituting in fact one of the great foundations of the continent. But when required believe that certain phases of this Trenton limestone make one of the great oil-rocks of our geological scale, one which produces from single wells 5,000 barrels of oil, or 15,000,000 cubic feet of inflammable gas it is hard to prevent our surprise passing into incredulity.

 

Surface indications of a sulphnretted and inflammable gas, escaping, from the rocky floor of the village of Findlay have been known since the country was settled. The gas had, in fact, been utilized in a small way, viz., in lighting a single residence for more than forty years, but in 1884 the influence of Pittsburg had made itself felt much of Ohio and drilling, was begun here. At a depth of 1,100 feet a respectable flow of gas was secured. The success of this well was the first step in by far the most remarkable development that has ever taken place in the geology of Ohio.

 

It was more than a year before a great gas well was discovered in Findlay, but the Karg well, which was completed in January, 1888, deserves this name. Its daily yield when first opened was not less than 14,000,000 cubic feet.

 

The discovery of oil followed that of gas by a short interval, but the prolific character of the new rock was not established till the latter half of 1886.

 

The rapid extension of productive territory and its equally rapid limitations, the developments of several distinct centres, as Bowling Green, Lima and St. Mary's, the great speculative excitement that broke out when the good fortune of the new gas-field began to be manufacturers and investors, and the wonderful developments that have since taken place in the line of manufactures industries, cannot be even touched upon in this connection. The salient points in of the new fields are brought out in summary that follows. The discovery comes from an unexpected quarter, viz., from the “black swam” of old time of Northwestern Ohio. Under its broad and level expanses a few hundred square miles have been found distributed through portions of five counties, within which are contained fountains of oil and reservoirs of gas of infinitely more value than any like accumulations hitherto discovered in the State, and fully deserving a place among the most valued repositories of these substances in any quarter of the world.

 

The leading facts pertaining to the field can be summarized as follows:

 

1. In fourteen of the northwestern counties of Ohio (and like conditions prevail in contiguous territory in Indiana), the upper beds of the Trenton limestone, which lie from 1,000 to 2,000 feet below the surface, have a chemical composition different from that which generally characterizes this great stratum. They are here found as dolomite or magnesian limestone instead of being, as usual, true carbonate of lime. Their percentage of lime, in other words, ranges between 50 and 60 per cent instead of between 80 and 90 per cent, as in the formation at large. These dolomites of Northwestern Ohio are mainly quite free from siliceous impurities. The dolomite composition seems to have resulted from an alteration of a true limestone. At least the occasional masses of true limestones charged with fossils, that are found on the horizon of and surrounded by the dolomite, are best explained on this supposition. In the change which has been endured, the fossils which the original limestones contained appear to have been for the most part discharged or rendered obscure, as is usual in this metamorphosis. The crystalline character of the dolomite is often very marked, and there results from it a peculiarly open or porous structure. Its storage capacity is much greater than that of ordinary oil sandstones and conglomerates so far at least as pores visible to the unaided eye are concerned. The change usually extends for ten to thirty feet below the surface of the formation. In some cases, however, sheets of porous dolomite are found as low as fifty feet and Very rarely as low as 100 feet below the surface.

 

The area occupied by this dolomite phase of the Trenton limestone in Ohio has already been indicated. The eastern and the southern boundaries pass through Lucas, Wood, Hancock, Allen, Auglaize and Mercer counties. It is possible that the line crosses some parts of Ottawa, Wyandot and Hardin counties.

 

There is good reason to believe that this phase extends far to the northward and westward, outside of the State limits to which it has here been traced. We know that the Trenton limestone is a dolomite when it pitches rapidly down from the northern boundary of Ohio to make the low-lying floor of the Michigan coal basin, and we also know that it is a dolomite when it rises from under that basin as a surface rock of the northern peninsula. In like manner it is a dolomite when it leaves the western boundary of the State under deep cover, and it is a dolomite when it reaches the surface once more in the Galena district of Illinois and Wisconsin.

 

 

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Logan counties, but beyond them the Trenton limestone is invariably found with a percentage of more than 75 per cent of carbonate of lime, and rarely with less than 10 per cent of silicious impurities. It is this last element, with but little doubt, that has resisted the dolomitization of the stratum throughout the southwestern quarter of the State and in all contiguous territory.

 

To the eastward of the line laid down in Northern Ohio, a less definite boundary is to be looked for. It is certain that small areas of porous dolomite are found, beyond the line here recognized as the termination of the Findlay phase of the Trenton limestone.

 

Within the limits named, the limestone of course has a considerable variety of grain and texture, but all of the analyses obtained show the stratum to be in the main a dolomite already stated there are occasional patches w islands of true limestone in this sea of dolomite.

 

2. A porous rock, buried 1,000 to 2,000 feet below the surface of Northwestern Ohio, will not be found empty. Nature abhors a vacuum. With what will its pores be filled? Mainly with salt-water of peculiar composition, possibly representing the brine of the ancient seas in which the limestone was laid down. Ninety-nine-hundredths, or perhaps nine hundred and ninety-nine-thousandths of the limestone will be thus occupied. The remaining hundredth or thousandth will be filled with the petroleum and gas which have, in the long course of the ages that have passed, been gathered from a wide and general distribution through the water into certain favored portions of the great limestone sheet.

 

3. This salt-water will be held under artesian pressure. The porous limestone containing it rises to-day in Michigan and Illinois, communicating there with surface waters. The pressure of this head of water will be felt through every portion of the porous rock, and when the stratum is pierced by the drill in the areas that are thus occupied, the salt-water will rise with more or leas promptness, depending on the varying degrees of porosity in the rock. The height to which the water will rise will seem to vary in wells, by reason of the different elevations of the locations at which they are drilled, but with reference to sea-level the water columns will be found to closely agree.

 

The same artesian pressure accounts for the force with which oil and gas escape when their limited reservoirs in the porous rock are tapped by the drill.

 

4. The accumulations of oil and gas in the porous rock depends altogether upon the attraction of gravitation. The lighter portions of the contents of the porous rock, viz., oil and gas, are forced by gravitation into the highest levels that are open to them. Everything turns on the relief of the Trenton limestone. The gas and oil are gathered in the arches of the limestone, if such they are. In default of arches the high-lying terraces are made to serve the same purpose, but the one indispensable element and condition of all accumulation is relief. A uniform and monotonous descent of the strata is fatal to accumulation of oil and gas where everything else is favorable. The sharper the boundaries of the relief, the more efficient does it become. Absolute elevation is not essential; all that is required is a change of level in the porous rock. Each division of the field has its own dead line or salt-water line. Salt-water reigns universal in the Findlay field 500 feet below sea-level, except where some minor local wrinkle may give a small and short-lived accumulation of oil or gas. In the Lima field the salt-water line has risen to 400 feet below tide; in the St. Mary's field to 300 feet below tide, and in the Indiana field to 100 feet below tide. These figures stand in every case for the lower limit of production, with the possible minor exceptions already noted. The rock-pressure of the gas decreases to the westward in proportion to this decreasing head of water-pressure.

 

The large accumulations are derived from the large terraces. The Findlay terrace, for example, consists of a very flat-lying tract, ten or twelve miles across in an east and west line, from which the connected areas of the Trenton limestone slope on every side, and to which, therefore, they are necessarily tributary. The gas terrace of Indiana is, by far; the largest of these several subdivisions of the field. The minor elevations of Oak Harbor, Tiffin and Bryan, for example, give rise to the local supplies of gas or oil in these districts respectively.

 

In conclusion, it is only necessary to repeat that natural gas is in all cases stored power, that there are no agencies in nature that are renewing the stocks which the rocks contain as rapidly as high pressure wells exhaust them, and that therefore economy should be observed from the outset in the use of this highly-valued source of heat and light. It is not strange that, when the surprising discovery is first made in any field, a most lavish use or rather a wanton waste of the gas is likely to prevail. It is hard to realize that such floods as rush forth can ever fail, but it is undoubtedly true that every foot of gas withdrawn brings nearer the inevitable exhaustion of the reservoir.

 

IV.

SOILS AND FORESTS.

 

 

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soils of the State. Large tracts of these excellent native soils are found in Jefferson, Belmont, Harrison, Monroe, Noble, Guernsey and Morgan counties. Wool of the finest staple in the country has long been produced on the hills of this general region.

 

Among the thinner and less productive soils which occupy but a small area are those derived from the Devonian shales. They are, however, well adapted to forest and fruit production. The chestnut and the chestnut oak, both valuable timber trees, are partial to them, and vineyards and orchards thrive well upon them. The north sides of the hills throughout this part of the State invariably show stronger soils than the southern sides, and a better class of forest growths. The locust, the walnut and hickory characterize the former. The native soils of the Waverly group and of the Lower Coal Measures agree m general characters. They are especially adapted to forest growth, reaching the highest standard in the quality of the timber produced. When these lands are brought under the exhaustive tillage that has mainly prevailed in Ohio thus far, they do not hold out well, but the farmer who raises cattle and sheep, keeps to a rotation between grass and small grains, purchases a ton or two of artificial fertilizers each year and does not neglect his orchard or small fruits, can do well upon them. The cheap lands of Ohio are found in this belt.

 

The other great division of the soils of Ohio, viz., the drift soils, are by far the most important, alike from their greater area and their intrinsic excellence. Formed by the cammingling of the glacial waste of all the formations to the north of them, over which the ice has passed, they always possess considerable variety of composition, but still in many cases they are strongly colored by the formation underneath them. Whenever a stratum of uniform composition has a broad outcrop across the line of glacial advance, the drift beds that cover its southern portions will be found to have been derived in large part from the formation itself, and will thus resemble native or sedentary soils. Western Ohio is underlaid with Silurian limestones and the drift is consequently limestone drift. The soil is so thoroughly that of limestone land that tobacco, a crop which rarely leaves native limestone soils, at least in the Mississippi valley is grown successfully in several counties of Western Ohio, 100 miles or more north of the terminal moraine.

 

The native forests of the drift regions were, without exception, hard wood forests, the leading species being oaks, maples, hickories, the walnut, beech and elm. The walnut, sugar-maple and white hickory and to quite an extent the burr oak, are limited to warm, well-drained land, and largely to limestone land. The upland clays have one characteristic and all important forest tree viz., the white oak. It occupies vastly larger areas than any other single species. It stands for good land, though not the quickest or most generous, but intelligent farming can always be made successful on white-oak land. Under-draining is almost always in order, if not necessary, on this division of our soils.

 

The regions of sluggish drainage, already referred to, are occupied in their native state by the red-maple, the elm and by several varieties of oaks, among which the swamp Spanish oak is prominent. This noble forest growth of Ohio is rapidly disappearing. The vandal-like waste of earlier days is being checked to some degree, but there is still a large amount of timber, in the growth of which centuries have been consumed, annually lost.

 

It is doubtless true that a large proportion of the best lands of Ohio are too well adapted to tillage to justify their permanent occupation by forests, but there is another section viz., the thin native soils of Southern Central Ohio, that are really answering the best purpose to which they can be put when covered with native forests. The interests of this art of the State would be greatly served if large areas could be permanently devoted to this use. The time will soon come in Ohio when forest planting will be begun, and here the beginnings will unquestionably be made. The character of the land when its occupation by civilization was begun in the last century was easily read by the character of its forest growths. The judgments of the first explorers in regard to the several districts were right in every respect but one. They could not do full justice to the swampy regions of that early day, but their first and second class lands fall into the same classifications at the present time. In the interesting and instructive narrative of Col. James Smith's captivity among the Indians, we find excellent examples of this discriminating judgment in regard to the soils of Ohio as they appeared in 1755. The "first class" land of that narrative was the land occupied by the sugar-tree and walnut, and it holds exactly the same place to-day. The “second class” land was the white-oak forests of our high-lying drift-covered districts. The "third class" lands were the elm and red maple swamps that occupied the divides between different river systems. By proper drainage, many of these last-named tracts have recently been turned into the garden soils of Ohio, but, for such a result, it was necessary to wait until a century of civilized occupation of the country had passed.

 

These facts show in clear light that the character of the soil depends upon the geological and geographical conditions under which it exists and from which it has been derived.

 

C.

THE CLIMATE OF OHIO.

 

 

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ples of both currents. All other winds that blow here are tributary to one or other of these great movements. The return trades or southwest winds are cyclonic in their character; the northwest winds constitute the anti-cyclone. The former depress the mercury in the barometer and raise it in the thermometer; the latter reverse these results The rains of the State are brought in by southwest winds; the few cases in which notable precipitation is derived from currents moving in any other direction than from the southwest really make no exception to the general statement, for in all such instances; he rain falls in front of a cyclone which is advancing from the Gulf of Mexico. The portracted northeast storms that visit the State at long intervals and the short southeast storms that occur still less frequently are n all cases parts of greater cyclonic movements of the air that originate in the southwest and sweep out to the ocean over the intervening regions.

 

Between the average summer and winter temperatures of the State there is a difference of at least 40° Fahrenheit. A central east and west belt of the State is bounded by the isotherms of 51° and 52°, the average winter temperature being 30° and the average summer temperature being 73°Southern Ohio has a mean annual temperature of 54° and Northern Ohio of 49°.

 

The annual range is not less than 100°; the maximum range is at least 1300; the extreme heat of summer reaching 100° in the shade, while the "cold waves" of winter sometimes depress the mercury to 30° below zero. Extreme changes are liable to occur in the course of a few hours, especially in winter when the return trades are overborne in a conflict, short, sharp and decisive, with the northwest currents. In such cases the temperature sometimes falls 60° in 24 hours, while changes of 20° or 30° in a day are not it all unusual.

 

The winters of Ohio are very changeable. Snow seldom remains thirty days at over the State, but an ice crop rarely fails in Northern Ohio, and not oftener than once in three or four years in other parts of the State. fn the southern counties cattle, sheep and horses often thrive on pasture grounds through the entire winter.

 

In spite of these sudden and severe changes in climate of Ohio is proved by every test to be excellently adapted to both vegetable and animal life. In the case of man and of the domestic animals as well, it certainly favors symmetrical development and a high degree of vigor. There are for example no finer herds of neat stock or sheep than those which are reared here.

 

The forests of the State have been already described in brief terms. The cultivated products of Ohio include almost every crop that the latitude allows. In addition to maize, which nowhere displays more vigor or makes more generous returns, the smaller grains all attain a good degree of perfection. The ordinary fruits of orchard and garden are produced in unmeasured abundance, being limited only or mainly by the insect enemies which we have allowed to despoil us of some of our most valued supplies. Melons of excellent quality are raised in almost every county of the State. The peach, alone of the fruits that are generally cultivated, is uncertain; there is rarely, however, a complete failure on the uplands of Southern Ohio.

 

The vast body of water in Lake Erie affects in a very favorable way the climate of the northern margin of the State. The belt immediately adjoining the lake is famous for the fruits that it produces. Extensive orchards and vineyards, planted along the shores and on the islands adjacent, have proved very successful. The Catawba wine here grown ranks first among the native wines of Eastern North America.

 

The rainfall of the State is generous and admirably distributed. There is not a month in the year in which an average of more than two inches is not due upon every acre of the surface of Ohio.

 

The average total precipitation of Southern Ohio is forty-six inches; of Northern Ohio, thirty-two inches; of a large belt in the centre of the State, occupying nearly one-half of its entire surface, forty inches. The tables of distribution show ten to twelve inches in spring, ten to fourteen inches in summer, eight to ten inches in autumn and seven to ten inches in winter. The annual range of the rainfall is, however, considerable. In some years and in some districts there is, of course, an insufficient supply, and in some years again there is a troublesome excess, but disastrous droughts on the large scale are unknown, and disastrous floods have hitherto been rare. They are possible only in very small portions of the State in any case. There is reason to believe, however, that the disposal of the rainfall has been so affected by our past interference with the natural conditions that we must for the future yield to the great rivers larger flood plains than were found necessary m the first hundred years of our occupancy of their valleys. Such, a partial relinquishment of what have hitherto been the most valuable lands of the State, not only for agriculture, but also for town sites and consequently for manufactures and commerce, will involve immense sacrifices, but it is hard to see how greater losses can be avoided without making quite radical changes in this matter.

 

 

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Are floods like these liable to recur at short intervals in the future? The conditions under which both occurred were unusual. Considerable bodies of snow lying on frozen ground were swept away by warm rains before the ground was thawed enough to absorb and store the water. These were the immediate causes of the disastrous overflows in both instances, and it may well be urged that just such conjunctures, are scarcely likely to recur for scores of years to come. But it is still true that we have been busy for a hundred years in cutting down forests, in draining swamps, in clearing and straightening the channels of minor streams, and finally, in underdrainng our lands with thousands of miles of tile; in other words, in facilitating by every means in our power the prompt removal of storm-water from the land to the nearest water-courses. Each and all of these operations tend directly and powerfully to produce just such floods as have been described, and it cannot be otherwise than that under their combined operations our rivers will shrink during summer droughts to smaller and still smaller volumes, and, under falling rain and melting snow, will swell to more threatening floods than we have hitherto known. The changes that we have made and are still carrying forward in the disposal of storm-water renders this result inevitable, and to the new conditions we must adjust ourselves as best we can.

 

 

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