448 - HISTORY OF MONTGOMERY COUNTY.

CHAPTER XV.

GEOLOGY OF MONTGOMERY COUNTY.

THE geological structure of Montgomery County is identical with that of several other counties in Southwestern Ohio, and the geological history. says Prof. Orton, is substantially the same. From a report made by that gentleman in 1870, and made a part of a volume on the geological survey of the State, the facts herewith presented were taken. Mr. Orton's observations were made in 1869, and appear to have been very thorough.

The surface rocks of Montgomery County present three distinct formations, viz., the Cincinnati, or blue limestone group. belonging to the Hudson River period of the Lower Silurian age; the Clinton group and the Niagara group, the latter two belonging to the upper division of the Silurian age. Above these are drift beds of varying thickness. These are given in their order, the blue limestone being the lowest. In the rocky beds here exposed are found the earliest forms of fossil organic life, of various characters, and of most interesting forms, often beautiful in the extreme. The highest land in the county is over 1.000 feet above the level of the sea, or about 600 feet above low-water mark on the Ohio River at Cincinnati. which is 432 feet above tide water. The Great Miami River and its tributaries-the Stillwater and Mad, with numerous smaller streams-furnish the drainage for this county. receiving the surplus from nearly its entire area.

Prof. Orton says in his report: " As all the strata that are met with in the county are in the main undisturbed, or very nearly horizontal, it is evident that the different levels of the county will be marked by different rock formations, or by different beds of the same formation. It is found, accordingly, that the blue limestone occupies all those portions of the count which are not more than 450 to 475 feet above low-water at Cincinnati, while the Clinton and Niagara formations are confined to those limited areas which are more than 150 to 475 feet above this level, or, in other words, to the hilltops and highest table lands of the county. In many instances, however. these formations are themselves overlaid with heavy beds of drift. Of the 350 feet extreme elevation above mentioned, it will be seen that the blue limestone series fills 225 feet, while the remaining 125 feet is divided among the Clinton. Niagara and drift in the following order: The Clinton holds an average of twenty feet. its thickness diminishing from thirty feet in the northern portions of the county to nine feet in the southernmost. The Niagara formation of the county has a maximum thickness of fifty feet, which. however. it rarely attains. and it is some times found in beds the aggregate of which is not more than five feet. A vertical section in the vicinity of Centerville, Washington Township, from the surface of the ground to the level of the river, would give approximately the following results: Drift, fifteen feet: Niagara, forty feet; Clinton, twenty feet; blue limestone, 225 feet; total, 300 feet. A section at Webber & Lehman's quarry, east of Dayton two miles, gives eight to twenty feet of drift sands or clays, ten feet Niagara, twenty feet Clinton and 150 feet blue limestone; total, 200 feet. A section at the Soldiers' Home. two miles west of Dayton, gives, drift, ten feet; Clinton, ten feet; blue limestone, 160 feet: total, 180 feet. The last two sections are drawn to the level of the river at Dayton."

HISTORY OF MONTGOMERY COUNTY. - 449

It is customary to unite the Clinton and Niagara groups under one designation "Cliff Limestone," and about one-fourth the area of Montgomery is occupied by these formations, the other three-fourths being taken up by the blue limestone. The blue limestone, which outcrops only in Southwestern Ohio, and the adjacent portions of Indiana, Kentucky and Tennessee, attains an aggregate thickness of more than 500 feet. "It is the geological equivalent of the shales and sandstones that are known as the Hudson River group in the State of New York. Its name indicates the color and composition of the rocks that belong to it. The blue limestone proper, however, is inter stratified with beds of a blue calcareous clay or marl that constitute, in many localities. the larger portion of the system. The solid rock occurs in eleven layers that sometimes reach a thickness of ten or twelve inches, but which generally vary from three to six inches in thickness. Both limestone and marl abound in admirably preserved relics of the living forms that inhabited the ancient seas in which these beds were formed. These fossils belong exclusively to the lower divisions of the animal and vegetable kingdoms. No remains of any vertebrated animal. and no traces of land vegetation have ever yet been discovered in the strata of this group. Sea weeds and sponges, beautiful star fishes and stone lihes of exquisite construction, corals in great variety and infinite number, molluscan shells of the great classes, so crowded as frequently to constitute the entire substance of the rock, and many species of trilobites, articulated animals of an order long since extinct, are found in all portions of the bedded rock and in its weathered exposures. The general character of these fossils would indicate that the beds were formed at the bottom of deep seas, and no mark of shore lines or other indications of shallow water ever occurs to contradict this inference."

Wherever the channels of the streams in the county are worn deep enough, the blue limestone is exposed, and it is evident that this formation underlies the entire county. To the northward, it extends beyond the county limits a distance of twenty miles or more, as shown in the beds of the Great Miami and Stillwater Rivers. It is inferred that the whole surface of Montgomery County was once covered with unbroken strata of this formation to the height of 450 feet or more above low-water mark at Cincinnati. The upper layers of the series, constituting from six to twenty feet, differ in mineral character from the lower beds, and are composed for the most part of red and yellow clays, and occasionally a yellowish, arenaceous limestone, which is quite, often made useful as a fire stone or building rock.

The Clinton formation, lying next above the blue limestone, is identical with the same formation in the State of New York, where it was originally classified an 1 named. It is a crinoidal limestone, some twenty feet in thick ness, the upper layers showing crystalline particles when fractured, and the lower ones inclining strongly to a sandy character. On this account, it has been frequently called sandstone, and, although that name would apply very well to portions of the formation, it must be remembered that it is formed of lime sand, instead of silica sand, silica being almost entirely wanting in the Clinton rocks of this region. " In color," says the authority before quoted, "these rocks have no uniformity, varying not only in different localities but often in closely adjacent beds, passing from a marble-like whiteness through various shades of gray, pink, yellow and red. The weathered surfaces have very generally a yellowish. rusty appearance, due to the oxidation of the iron that the rocks contain. The crystalline beds take a good polish, constituting a marble of attractive appearance. The Harrisburg and Ludlow 'Marbles' are examples of this quality of the formation."

The rate of growth of this rock appears to have been very slow, no sedi-

450 - HISTORY OF MONTGOMERY COUNTY.

ments having contributed thereto, the strata being composed almost wholly of the broken stems and cups of crinoids or stone lilies, Sometimes, associated with them, are found representatives of animal groups named in the blue lime stone series, among them being chain corals as distinct characteristics. The Clinton stone has received several local names in the county, as " fire stone," " rotten limestone," "bastard limestone" and, among quarrymen it is sometimes called " pink eye." Above it and interposing between it and the Niagara limestone, is a layer of fine-grained marl, from two to six inches in thickness. which belongs to the Clinton group. It abounds in the "free, perforated. disc-like joints of crinoidal stems of very large species, and certain shells occur here that have not been found elsewhere in the series. As a general rule, the Clinton rock is not even bedded, but where raised in the quarries come.; out in irregular masses.''

The Niagara formation is not as uniform in character as the lower groups. "It consists in all cases of even-bedded limestones and marls, it is true, but the limestones have very different degrees of purity, while in hardness, compactness, color and the presence or absence of fossil contents, they have a very wide range. The celebrated Dayton stone-' Dayton marble,' it is sometimes styled may be assumed as the standard of excellence in this series; but different localities exhibit every degree of gradation, from the admirable qualities of this stone, in compactness, durability and color, to the worthless, 'yellowback' of the quarrymen, or to the unconsolidated clays that are frequently found as its equivalent. In Montgomery County, the lower layers of the Niagara rocks are always the firmest and most valuable, the five to ten feet immediately overlying the Clinton, constituting in almost every case the sources from which the Dayton stone is derived. The varying thickness of the formation in different localities has already been noted, the limits having been given as five to fifty feet. From the fact that so great variety in composition is found in these rocks, we are warranted in concluding that the Niagara strata were not originally of uniform thickness, as the beds of the previous groups seem to have been. It may be that the higher degrees of excellence in the stone were connected with a slower rate of growth It is at all events true that the most valuable deposits of this series in the county are in every case shallow. The lower beds contain but very few fossils, some circular corals and very rarely a bivalve or chambered shell, making out the list, while in higher portions of the group the strata are frequently crowded with fossils, which differ almost. entirely in species from those that are found in the lower groups. One peculiarity of these fossils is that they occur almost always as internal casts, the outer shell or investment having been dissovled and carried away during the past conditions of the rock. One of the most noticeable of all these forms of ancient life is the large bivalve shell, Pentamerous oblongus, known sometimes as the 'deer-foot shell' and quite frequently identified as a petrified hickory nut. The sections of a large chambered shell, of the genus Octhoceras, are also frequently met with, and are sometimes mistaken by the ignorant for the backbones of fishes or serpents. The area occupied by the Niagara rocks is not probably more than one-half of that which the Clinton covers. There seems, however, no reason to doubt that both of these members of the cliff formation were once extended over the whole surface of the county, as their present dis tribution can be satisfactorily explained by reference to erosive agencies that are known to have been at work upon them agencies some of which are still continuing their destructive tasks. The Clinton and Niagara in th eastern portions of the county occur altogether in insulated masses or islands. on the ridge between the two Miamis, and all the water-courses that flow from these high grounds have already worn their channels deep into these rocks, not

HISTORY OF MONTGOMERY COUNTY. - 451

infrequently through them, into the underlying blue limestone series. There is, however, a manifest shallowing of the cliff rocks as we go southward, the Clinton diminishing to nine feet near the southern line of the county, apparently indicating that the blue limestone regions southward were, even at this early time, raised above the surface of the seas, or in other words that they were never covered by the limestones of the succeeding cliff formation."

The deposits of the drift period cover all of the foregoing formations to varying depths, throughout nearly their entire extent, and in some instances miles intervene between the exposures of the rocky beds. These drift deposits vary greatly in thickness; nature of materials of which they are composed, and the order of arrangement of these materials; therefore, it is almost impossible to find two sections of drift beds that will agree in every particular. Prof. Orton speaks of the drift in the following language:

" Before describing the leading characteristics of these beds, it will be proper to call attention to an interesting fact that must be referred to the same agencies by which the. drift itself is explained. Considerable portions of the rocky surface of the county have been planed, polished, striated and grooved by heavy masses of ice-inclosing sand, gravel and bowlders-moving over them. These phenomena can be best observed in the firmer beds of the Niagara limestone, occupying as they do the highest table lands of the county. but they are by no means confined to them. The groat belt of quarries south east of Dayton furnish fine exhibitions of this agency. Indeed, these naturally planed surfaces are frequently turned to account for door-steps, flagging stones and other similar uses. It is altogether probable that the whole surface of the county has been exposed to the abrading agencies of the glacial sheet, as we find the marks of these agencies at every point where the rocks are firm enough to retain them. The unconsolidated beds of the Niagara rocks have been in large measure removed by the same force that has planed the harder surfaces as is evident from an inspection of those higher portions of the system that still remain. This polished surface of the Niagara rock is generally covered with yellow clays intermingled with gravel and bowlders. Sometimes heavy granitic blocks have been left in the clay in almost immediate contact with the bedded rock, their own surfaces having been planed and scored by the service to which they have been put. We see in them the implements of abrasion the engraving tools-left where the work was done. The thickness of these clay deposits varies from ono foot to thirty feet, and the upper portions are almost always freer from gravel than the lower portions. Occasionally a limited deposit of blue clay is found on the surface of the rocks, but for the most, part these beds of blue clay, when they occur, are found overlying yellow clays or beds of gravel, in pockets of small extent. Fragments of drifted coniferous wood are sometimes found buried deep in these deposits. Next in importance to the yellow clays are. the beds of sand and gravel, of which the drift beds are largely composed. They sometimes overlie the clays, are sometimes inter stratified with them, and sometimes they repose directly upon the surface of the rocks. The gravel contains representatives of all the formations that are found to the northward within the limits of the State, viz., blue limestone. Clinton, Niagara, water lime, coniferous and slack slates, and a considerable part of it is derived from the metamorphic rocks of the Lake Superior region and from the Canadian highlands. To the same source must be referred the sand as no silicious formation of any considerable extent occurs between these deposits and the line of the great lakes. The sand and gravel have a thickness of at least 100 feet in many instances. The deposits are always distinctly stratified, and exhibit many alternations of fine and coarse materials that be token considerable changes in the conditions of their formation. They often

452 - HISTORY OF MONTGOMERY COUNTY.

show, especially in the beds that, occupy the lower levels of the county, beach structure, or marks of the action of water that could only be impressed upon them while they lay at or near the surface. The sand and gravel are sometimes cemented into massive blocks by the deposition of carbonate of lime from the spring water that flows over and through them. Recourse was formerly had to these conglomerates for building stone, but it was found that they were worthless for such purposes, as they cannot withstand the action of frost.

" The lost rocks --bowlders, hard-heads, gray-heads, as they are frequently designated-constitute too important a feature of the geology of the county to be omitted in this review. They are irregularly distributed over the face of the county, sometimes thickly sown in belts of several miles in length and breadth, with tolerably definite boundaries. and sometimes scattered singly at wide intervals. They occur through the whole range of the drift beds, but are far more abundant in the upper portions than in any other. As in the case of the gravel they are all of northern origin, and by far the largest number has been brought from beyond the great lakes. These bowlders weigh not less than 160 pounds to the cubic foot, and the total weight of single blocks sometimes exceeds ten tons."

Building Rock.-The three rock formations exposed in Montgomery County furnish abundant material for this use. "The blue limestone affords, in numberless exposures, a building stone that is accessible, easily quarried, even bedded, of convenient thickness and very durable. It possesses, however, but little susceptibility of ornamentation. The thinness of its beds, its hardness and brittleness, stand in the way of its improvement by dressing, and its color is too dark to please the eye when it is exposed in large surfaces of masonry. The Clinton rock, in all of its beds-but especially in its upper ones - affords a building stone that would ba highly valued were it not for the close proximity, in most instances, of the quarries of the Niagara group. A similar statement can be made in regard to the products of the, blue limestone quarries of the county. When the Clinton stone is first raised from the quarry, it is frequently so soft as to be easily worked; but when the water has escaped from it, it becomes a measurably firm and enduring stone. Some of its beds, indeed, are crystalline, or semi-crystalline in structure, and leave nothing to be desired as far as durability is concerned. As already remarked, the Clinton group exhibits a great variety of colors, and some of these shades are very pleasing to the eye a fact which makes this stone susceptible of fine architect ural effects. The greatest objection to this series is that it is not generally even-bedded. The lower strata are very seldom so. The Niagara group, however, furnishes the best building stone, not only of Montgomery County, but of the whole Miami Valley as well. Indeed, for many purposes it is inferior to none. Occurring as it does, in even-bedded layers of from four to twenty inches in thickness, it is adapted to the purposes of both light and Heavy masonry. It is homogeneous in structure, has a beautiful color, takes ornamentation quite kindly and is durable to any required degree. The value that is attached to it can he judged from the fact that in some of the quarries nearest to Dayton, the stone sells in the ground for $17.50 per rod, or $2,800 per acre, the title to the land not being alienated. In these quarries there is less than five feet of workable stone, and this can only be reached by removing from five to twenty feet of drift clays and sands. The supply of the rock even in this, its best estate, is inexhaustible, but the expense of transportation shuts out at present from the general market all the quarries that are more than three or four miles distant from Dayton. The quarries that lie outside of these limits, however, are invaluable for neighborhood supplies. The quality of the stone, when perfect in every other respects, is sometimes injured by the

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PAGE 454 - PICTURE OF WILLIAM M. KELSEY, WASHINGTON TP

PAGE 455 - PHEBE KELSEY (DECEASED), WASHINGTON TP

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occurrence of crystals of iron pyrites, which weather into brownish stains when exposed to the air and disfigure the surface.

"In addition to the kind of rock already named, there is in the county a large supply of Niagara rock that falls short of the typical excellence in hardness and color, but which still constitutes a very serviceable and valuable de posit. These beds of inferior quality are sometimes the precise stratigraphical equivalents of the true Dayton stones; that is, they immediately overlie the Clinton formation, but generally they occur at a higher level in the series. The differences in color and hardness alluded to seem connected with differences in chemical composition, the Dayton stone being a nearly pure carbonate of lime, while the inferior grades are composed of the carbonates of lime and magnesia. The color of these last-named beds is not constant., various shades of drab and yellow alternating with shades of blue. sometimes even in the same layer of rock. In durability they seem in no way inferior to the standard Dayton stone. The bowlders of the drift are also available for building purposes. They form, in some parts of the county, the main supply for foundations, and, when treated with skill, give excellent results."

Brick. Draining-Tile and Pottery Clays. - Outside of the alluvial bottoms, nearly every section of the county furnishes, from its drift beds, material from which brick can be manufactured. the yellow clays overlying the Niagara rock in the higher table lands being by far the best for the purpose. In many cases, the walls of a building can be constructed of bricks of the best quality made from the clay taken from its site. " Beds of blue clay are also abundant, generally at lower levels of the county, from which draining-tile and pottery can be made. For these purposes, the blue and yellow clays are generally mixed, the blue clay imparting the necessary strength and the yellow counteracting the tendency of the former to shrink and crack in the process of baking. The importance of drain-tile in agriculture begins to be understood. Hundreds of thousands of tiles are now manufactured annually, with a steadily increasing demand. A third variety of clay is found within the county, in quite limited deposits compared with the preceding. It also is called blue clay, but it differs from the ordinary blue clay in containing no iron. It is converted by burning into a cream-colored brick of the same general character as the Milwaukee brick. It is generally very fine grained, and has been quite largely used as mineral paint. In composition, it consists of little besides alumina, silica and lime. There is no doubt that these deposits will be regarded with increasing interest, as their advantages for architectural purposes come to be recognized. The heaviest accumulation of this clay now known in Southern Ohio occurs near Springfield, Clark County, and it has already been turned to good account in the manufacture of Milwaukee brick.

" Firestone.-A stone that can endure the action of heat, admits of many useful applications. Two of the bedded rocks of the county have considerable local reputation as firestones, viz., the sandy limestones that make the upper most beds of the blue limestone series and the Clinton group. This latter rook certainly answers a tolerable purpose for chimney jambs and kindred uses. It is not easy to see what there is in its composition that enables it to resist unchanged the agency of fire, as analyses show it to be a true limestone of a good degree of purity. Experience, however, abundantly demonstrates its value in this regard. Chimney-jambs can be shown that have stood over fifty years in service. Farmers are willing to transport it for miles to lay up the arches of their sugar camps. It must be added that the different beds of the series have very different qualities in this respect, the middle and lower layers furnishing the best firestone, and there is no doubt that the quality in its highest exhibition is local.

"Lime.- As lime is the great cement employed alike in nature and by hu-

458 - HISTORY OF MONTGOMERY COUNTY.

man art, the sources of its supply are of more economical value to any community than are the supplies of building stone and brick clay even. All the bedded rocks of the Miami Valley, and portions of the drift as well, furnish materials from which excellent lime can be made. It is needful, however, to remark that the terms limestone and lime do not convey any precise information as to the chemical composition of the substances to which they are applied. Limestones always contain carbonate of lime, it is true: but besides this they generally contain various compounds and various proportions of magnesia. alumina (clay), silica (sand) and iron. The limestones of this region that can be burned into valuable lime may be divided into two classes, according to their chemical composition. The first group comprises those rocks that consist mainly of carbonate of lime, or that contain at least 85 per cent of this substance. The second group is made up of the dolomites, or magnesian limestones, which have at least 40 per cent of carbonate of magnesia in their composition. Silica, alumina and iron are found in small and varying proportions in each division. The properties of these limes are very different. Those of the first class require to be submitted to a higher temperature in burning than the second. They slake promptly and thoroughly, and in the operation evolve a great degree of heat. From this last fact they are termed `hot' or `fiery' limes. They `set' or harden so soon that but two or three bricks can be laid with one spreading of mortar, and walls that are made of them have a tendency to 'chip-crack.' It is quite likely that this last-named property can be attributed in some degree to the silica and alumina which they contain. The second group contains those limes that are called `cool.' They do not give out so much heat in slaking as the limes of the first class, nor do they `set' as soon. From five to twenty bricks can be laid with a single spreading of mortar, and in plastering a corresponding advantage can be obtained. On purely practical grounds, the builders of Southwestern Ohio have come to recognize the greater desirability of the limes of the last named class. and none others can now find a market in the cities and towns of this portion of the State. To the first series belong the blue limestones, the Clinton group and the Dayton beds of the Niagara group. The limes of the second series are all obtained from the upper or Niagara division of the cliff limestones, and the kinds of rocks from which they are derived constitute almost the entire mass of this formation. It thus appears that the Niagara group in Ohio is a true magnesian limestone, as all the members of this same great series throughout its wide western expansion--in Michigan, Wisconsin. Illinois, Iowa and Minnesota-have uniformly been found to be. The only exception to these statements as to the composition of the Niagara series is found in some of its lowermost beds, where in limited and isolated areas the Dayton stone and its equivalents occur. This stone has already been referred to the true limestones, an analysis of it made by Dr. Locke, in 1835. showing that it contains 92 per cent of carbonate of lime. While with this exception the whole Niagara series consists o£ magnesian limestones, it would be wrong to conclude that every portion of this series, taken indifferently, can be burned into valuable lime. The quarries that are worked for lime burning at Cedarville. Yellow Springs. Springfield, Moore's quarries below Springfield, Wilson's quarries north of Dayton, and a few others less widely known, furnish the most valuable limes of the Miami Valleys and largely supply the markets of Cincinnati, Dayton, Hamilton, Springfield, Xenia and the remaining towns and villages of this section. These quarries all lie in the same geological horizon, viz., between 50 and 100 feet above the base of the Niagara rocks. They begin in or above the strata that contain the large shell Pentamerous oblongus, and generally include from ten to twenty feet that overlie the Pentamerous beds a. series of thin and irregularly bedded strata, valueless for building stone, largely filled with crin-

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oidal fragments. The strata that underlie the Pentamerous beds consist of blue and drab magnesian limestones, which cannot be burned into a good article of common lime, but which there is good reason to believe possess in greater or less degree the properties of hydraulic cement or water lime. A sample from the quarries of W. Sroufe, Esq., Yellow Springs, when analyzed, was found to agree very closely with a magnesian limestone of France that is cited by Vicat as an excellent hydraulic cement. The same rock, when treated in laboratory experiments, indicates an eminent degree of hydraulic energy."

An analysis of the Clinton limestone from Centerville. Montgomery County, showed that it contained the following elements:

Carbonate of lime ................. 86.30 Silica...............................0.85

Carbonate of magnesia.. . ......11.84 Alumina and iron.............0.40

Total . . . .. . . .. . . .. . . .. . . . . .. . . .. . . .. . . .. . . .. . . .. . . .. . 98.89

This compares well with the analyses of rocks from the blue limestone and Niagara beds in various places, being about the average of all.

"Mineral Paints.- The materials from which mineral paints have been manufactured in this portion of the State are all obtained from the beds of drift. The second variety of blue clay, already described, is principally used for this purpose." A company vas organized at Miamisburg about 1867 or 1868, and their sales, in 1869, aggregated over 100,000 pounds, which included a considerable portion of lead. The bed of clay which is turned to most account is situated on Hole's Creek, at no great elevation above the Miami River. The clay is identical in composition with the heavy bank near Springfield, and closely resembles the Milwaukee brick' clay in composition." An analysis of the Hole's Creek clay is herewith presented:

Water in sample dried at 212 ........ 0.80 Alumina soluble .................. 6.05

Organic matter..................... . ...... 2.35 Sesquioxide of iron..............13.00

Silica. . . .. . . .. . . .... . . ... . . .. .....35.56 Carbonate of lime.. . ... . .....39.18

Alumina as silicate . . . .. . . .. . . ..13:59 Carbonate of magnesia......... 7.04

Total............. ...................................................97.57

"Many of the gravel beds of the drift contain accumulations of ocher more or less extensive. and occasionally deposits of the same substance are found unmixed with gravel. The ocher can be separated from the gravel by washing, and proves to be of fair quality. A large deposit of this ocherous gravel is to be found on the north bank of Twin Creek. one mile east of Germantown, Montgomery County. A bed of brown coal, that occurs in the same gravel bank, has been turned to account for the manufacture of black paint. Mastodon remains and phosphate of iron are found also in this locality. Taking all things into account, no more interesting section of the drift is to be found in this region than the Germantown ocher bank.'

Gravel. -It is not easy to set a proper estimate upon the beds of sand and gravel of the county until a comparison is instituted between a region well supplied with such accumulations and another which is destitute of them. The gravel knolls and ridges with which, in the southern and eastern portions of the county, almost every farm abounds, afford very desirable building sites. and are generally selected for such purposes. Sand of the best quality for mortar, cement and brick making, is everywhere within easy access. An inexhaustible supply of excellent materials for road making what is frequently designated clean limestone gravel,' though in reality largely composed of granitic pebbles is found in the drift deposits, from which hundreds of miles of turnpikes have been already constructed in the county, thus affording free communication between farm and market at all seasons of the year. The smaller bowlders, of Canadian origin, are selected from the gravel banks for paving-stones, and transported to the neighboring cities. In regions where stone suitable for macadamized pikes can be obtained, good roads can be had, even though gravel

460 - HISTORY OF MONTGOMERY COUNTY.

is wanting, but at largely increased expense above that of gravel turnpikes. The districts which are supplied with neither can certainly never compete in desirability with these gravel-strewn regions.

"The agricultural relations of the different formations of Montgomery County remain to be briefly discussed. Only those points will be touched upon which are especially noticeable. From what has been already said of the distribution of the drift, it may be inferred that this formation will conceal or obscure all the rest, and, to a considerable extent, this will be found to be the case. There are large areas in which the underlying rock seems to have no direct effect upon the superficial beds, further than to control the general feature of their arrangement. In such cases the soil depends directly upon the composition of the drift beds. and will be found light, warm and dry, or heavy, cold and wet, according as sand or clay predominates in these beds. There are, however, several varieties of soil that receive their leading characteristics directly from the rock with which they are associated. The high table lands of the Niagara limestone, which are mostly confined to the northern portions of the county, furnish the first example. These limestones are often covered with but a shallow deposit of clay. yellow originally, but blackened by organic matter for a foot or two from the surface. These table lands hold so nearly a horizontal position that the streams that have their sources in them have but a sluggish flow. Indeed, these districts, until that' are, cleared and ditched, are almost always marshy in their conditions, and, though occupying the highest level of the county, are universally spoken of as low-lying lands. They contain abundant elements of agricultural wealth, but demand a more painstaking and scientific kind of treatment than our farmers are generally willing to bestow. In default of this, they are largely dependent on the seasons-favorable seasons bringing a large reward and unfavorable ones being marked by failures more or less complete. The water supply in these locations is generally derived from drilled wells, which it is sometimes necessary to carry to a depth of sixty feet, though one-third of this depth usually suffices. In their present condition they constitute the lowest-priced lands of the county, unless, as in a few instances, their contiguity to markets has led to their thorough improvement. In these cases, they show themselves to be possessed of admirable qualities for farming lands. and also give examples of what may be hoped for from the remainder of this formation. A belt of still more pronounced character, in which the agricultural relations are still more closely connected with the geological structure, is furnished in the line of junction of the blue limestone and Clinton formations, or, what is the same thing, in the line of junction of the Lower and Upper Silurian.

"It will be remembered that the uppermost beds of the blue limestone series consist, for the most part, of unconsolidated clays, while the lower portion of the overlying cliff formation, viz.. the Clinton rock, is largely com posed of beds of a porous sandstone (lime sand). The result of this order of sequence is that the clays of the blue limestone series are the water-bearers of the region which they occupy, as was long ago pointed out by Dr. Locke. The strongest springs of Southwestern Ohio mark quite accurately this line of junction. The clays constitute a gradual slope-sometimes one-fourth of a mile in breadth from the foot of the cliff. The springs that flow out along the line gave, before the country was cleared, a marshy character to this belt, as is shown in the black and fertile loam by which it is still marked. They also serve to distribute, to some degree, the waste of the cliff to the slope below.

"The early settlers located their homes in the vicinity, of these perennial springs, and the prosperity which has attended The labor of husbandry upon these fruitful tracts is well attested in the comfortable and tasteful homes which mark the lowermost outcrop of the cliff limestones. Perhaps no other

HISTORY OF MONTGOMERY COUNTY. - 461

geological boundary of the State is so definitely connected with human interests. The blue limestone• give rise, in limited areas, to soils of great fertility. The rocks of this age, for the most. part, are covered deep by beds of modified drift, lying as they do at a lower level than the other rocks of the county; but occasionally. a slope is found that is derived directly from the weathering of the blue limestone beds. The rocks of this series are rich in phosphates, a fact which accounts for their value in agriculture. An analysis by Dr. Wormley, chemist of the survey, give sixteen-hundredths of 1 per cent of phosphoric acid in the bedded clays. This proportion shows that a soil one foot in depth. formed from the weathering of these clays. would contain to the acre very nearly 7,500 pounds, of phosphoric acid a substance indispensable to the growth of the higher forms of vegetation. The celebrated blue grass country of Kentucky is derived directly from the rocks of this formation, without the addition of our drift clays and sands.

"A discussion of the drift in this connection would be, under another name, a treatise upon the general agriculture of the county, and cannot here be entered upon. Suffice it to say that the character of the drift deposits largely determines for each locality the market value of.its lands, the kinds of crops that can be cultivated with profit, the nature and amount of its water supply, the quality of its highways, its degree of healthfulness. and, in short, its general desirability for human occupancy.

"Attention will be called to but one more point in this connection: The river valleys of Southwestern Ohio are known to have been deeper than they are at present. In other words, they are now partly filled with drift, and the streams no longer flow upon rocky beds. Not only is the absolute depth of the valleys diminished by these deposits, but the abruptness of the declivity is greatly modified by them. Instead of a precipitous descent over the naked edges of the rocks. a well-graded slope, consisting frequently of the best road gravel leads from the highlands to the river bottoms. The nature and order of the succession of the formations previously described, renders it certain that were it not for the interposition of the drift, the line of junction of the blue limestone and cliff formation would be an impassable belt of miry clay for one-third of the year, unless relieved by expensive artificial roads. A similar state of things would be found throughout much of the blue limestone regions. The leading points in the geology of the line of junction of the Lower and Upper Silurian formations of Southwestern Ohio have now been briefly noticed. * * * Among the points of economical interest may be mentioned the establishment of the limits within which the Dayton stone is to be found, lying as it does at the very base of the Niagara series, the recognition of the fact that the best lime of this part of the State comes from a horizon about 100 feet higher in the series than that which the Dayton stone occupies, with the consequent knowledge of the areas within which it occurs. and the discovery that certain beds of the same series afford hydraulic lime of excellent quality. The great value of the Dayton stone naturally leads to considerable interest in the discovery of new deposits of it. A safe guide for all future investigations will be found in the order of sequence of the great formations, an order which practical men. engaged for years in quarrying the stone, have generally failed to recognize.''

An extensive bed of peat was discovered, some years since, one mile east of Germantown, Montgomery County in and directly above the channel of Twin Creek of which a very interesting account is given in the appendix to the reports of the Ohio geological survey of 1869. This volume may be found among the books of reference in the public library at Dayton, and to it we would refer all interested. as it is not thought best to extend this chapter to greater length.