Montgomery County, Ohio - Chapter 15: Geoloc4y of Montgomery County, 1882

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

The surface rocks of Montgomery County present three distinct for: tions, viz., the Cincinnati, or blue limestone group, belonging to the Hud i River period of the Lower Silurian age; the Clinton group and tho Miag : group, the latter two belonging to the upper division of the Silurian a Above these are drift beds of varying thickness. These are given in their der, the blue limestone being the lowest. In the rocky beds here exposed i found the earliest forms of fossil organic life, of various characters, i of most interesting forms, often beautiful in the extreme. The highest L in the county is over 1,000 feet above the level of the sea, or about 600 i above low-water mark on the Ohio River at Cincinnati, which is 482 feet ab tide water. The Great Miami River and its tributaries - the Stillwater Mad, with numerous smaller streams - furnish the drainage for this coin receiving the surplus from nearly its entire area.

Prof. Orton says in his report: " As all the strata that are met with the county are in the main undisturbed, or very nearly horizontal, it is evio that the different levels of the county will be marked by different rock formatk - or by different beds of the same formation. It is found, accordingly, that 1 blue limestone occupies all those portions of the county which are not more t'i 450 to 475 feet above low-water at Cincinnati, while the Clinton and Niag: formations are confined to those limited areas which are more than 450 to feet above this level, or, in other words, to the hilltops and highest table la; of the county. In many instances, however, these formations are themsei overlaid with heavy beds of drift. Of the 350 feet extreme elevation ab mentioned, it will be seen that the blue limestone series tills 225 feet, wi the remaining 125 feet is divided among the Clinton, Niagara and drift in following order: The Clinton holds an average of twenty feet, its thick! i diminishing from thirty feet in the northern portions of the county to n feet in the southernmost. The Niagara formation of the county has a tuii mum thickness of fifty feet, which, however, it rarely attains, and it is so: times found in beds the aggregate of which is not more than live feet. A v tical section in the vicinity of Centerville, Washington Township, from j surface of the ground to the level of the river, would give approximately following results: Drift, fifteen feet; Niagara, forty feet; Clinton, twe feet; blue limestone, 225 feet; total, 300 feet. A section at Webber & I man's quarry, east of Dayton two miles, gives eight to twenty feet of <h sands or clays, ten feet Niagara, twenty feet Clinton and 150 feet blue li 1 stone; total, 200 feet. A section at the Soldiers' Home, two miles^wes1 Dayton, gives, . drift, ten feet; Clinton, ten feet; blue limestone, lo0 f total, 180 feet. The last two sections are drawn to the level of the rivei Dayton. "

It is customary to unite the Clinton and Niagara groups under one designapn " Cliff Limestone," and about one-fourth the area of Montgomery is isc'pied by these formations, the other three- fourths being taken up by the it' limestone. The blue limestone, which outcrops only in Southwestern } ), and the adjacent portions of Indiana, Kentucky and Tennessee, attains t ggregate thickness of more than 500 feet. "It is the geological equivaof the shales and sandstones that are known as the Hudson River group .e State of New York. Its name indicates the color and composition of icocks that belong to it. The blue limestone proper, however, is interstrati - »With beds of a blue calcareous clay or marl that constitute, in many lo- . dies, the larger portion of the system. The solid rock occurs in eleven v:s that sometimes reach a thickness of ten or twelve inches, but which genr.sjy vary from three to six inches in thickness. Both limestone and marl i; nd in admirably preserved relics of the living forms that inhabited the went seas in which these beds were formed. These fossils belong exclusively e lower divisions of the animal and vegetable kingdoms. No remains of rVertebrated animal, and no traces of land vegetation have ever yet been sivered in the strata of this group. Sea weeds and sponges, beautiful star da and stone lilies of exquisite construction, corals in great variety and inri; number, molluscan shells of the great classes, so crowded as frequently ustitufce the entire substance of the rock, and many species of trilobites, lulated animals of an order long since extinct, are found in all portions of ebedded rock ami in its weathered exposures. The general character of m fossils would indicate that the beds were formed at the bottom of deep a and no mark of shore lines or other indications of shallow water ever ocifto contradict this inference."

Wherever the channels of the streams in the county are worn deep enough, eilue limestone is exposed, audit is evident that this formation underlies entire county. To the northward, it extends beyond the county limits a s nee of twenty mile3 or more, as shown in the beds of the Great Miami and S water Rivers. It is inferred that the whole surface of Montgomery County i nice covered with unbroken strata of this formation to the height of 450 epr more above low-water mark at Cincinnati. The upper layers of the r,s, constituting from six to twenty feet, differ in mineral character from tiie'ower beds, and are composed for the most part of red and yellow clays,

The Clinton formation, lying next above the blue limestone, is identical : it the same formation in the State of New York, where it was originally ajjified an 1 named. It is a crinoidal limestone, some twenty feet in thick- " the upper layers showing crystalline particles when fractured, and the vjr ones inclining strongly to a sandy character. On this account, it has m frequently called sandstone, and, although that name would apply very e to portions of the formation, it must be remembered that it is formed of n sand, instead of silica sand, silica being almost entirely wanting in the hjfen rocks of this region. " In color," says the authority before quoted, tjrae rocks have no uniformity, varying not only in different localities but -L in closely adjacent beds, passing from a marble-like whiteness through ujus shades of gray, pink, yellow and red. The weathered surfaces have generally a yellowish, rusty appearance, due to the oxidation of the o that the rocks contain. The crystalline beds take a good polish, coasting a marble of attractive appearance. The Harrisburg and Ludlow ' marls ' are examples of this quality of the formation." ments having contributed thereto, the strata being composed almost wholly the broken stems and cups of crinoids or stone lilies, Sometimes, associal with them, are found representatives of animal groups named in the blue lin stone series, among them being chain corals as distinct characteristics. 1 Clinton stone has received several local names in the county, as " fire stom " rotten limestone," "bastard limestone" and, among quarrymen it is son times called " pink eye." Above it and interposing between it and the Mag! limestone, is a layer of fine-grained marl, from two to six inches in tliiekne which belongs to the Clinton group. It abounds in the ' ' free, perforate disc-like joints of crinoidal stems of very large species, and certain shells i cur here that have not been found elsewhere in the series. As a general ru the Clinton rock is not even bedded, but where raised in the quarries comas c in irregular masses."

The Niagara formation is not as uniform in character as the lower grouj "It consists in all cases of even-bedded limestones and marls, it is true, l the limestones have very different degrees of purity, while in hardness, co pactness, color and the presence or absence of fossil contents, they have a vt wide range. The celebrated Dayton stone - ' Dayton marble,' it is someth styled - may be assumed as the standard of excellence in this series; but d ferent localities exhibit every degree of gradation, from the admirable qualit of this stone, in compactness, durability and color, to the worthless, 'yelk back ' of the quarrymen, or to the unconsolidated clays that are frequen found as its equivalent. In Montgomery County, the lower layers of the Ni; ara rocks are always the firmest and most valuable, the five to ten feet imn diately overlying the Clinton, constituting in almost every case the sources i'r. which the Dayton stone is derived. The varying thickness of the formati in different localities has already been noted, the limits having been given five to fifty feet. From the fact that so great variety in composition is fon in these rocks, we are warranted in concluding that the Niagara strata wc not originally of uniform thickness, as the beds of the previous groups seem have been. It may be that the higher degrees of excellence in the stone w< connected with a slower rate of growth. It is at all events true that the mi valuable deposits of this series in the county are in every case shallow. T lower beds contain but very few fossils, some circular corals and very rarelj bivalve or chambered shell, making out the list, while in higher portions of t group the strata are frequently crowded with fossils, which differ almost e tirely in species from those that are found in the lower groups. One pee-ulia; ty of these fossils is that they occur almost always as internal casts, the out shell or investment having been dissovled and carried away during the p; conditions of the rock. One of the most noticeable of all these forms of i cient life is the large bivalve shell, Pentamerous oblongus , known sometimes the ' deer-foot shell ' and quite frequently identified as a petrified hickory ui The sections of a large chambered shell, of the genus Ortlioceras, are al frequently met with, and are sometimes mistaken by the ignorant for the ba( bones of fishes or serpents. The area occupied by the Niagara rocks is r probably more than one-half of that which the Clinton covers. ' There seen however, no reason to doubt that both of these members of the cliff formati were once extended over the whole surface of the county, as their present d tributiou can be satisfactorily explained by reference to erosive agencies tl are known to have been at work upon them - agencies some of which are st continuing their destructive tasks. * '* The Clinton and Niagara in t eastern portions of the county occur altogether in insulated masses or i slant on the ridge between the two Miamis, and all the water-courses that flew fre these high grounds have already worn their channels deep into these rocks, n

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

The deposits of the drift period cover all of the foregoing formations to a ing depths, throughout nearly their entire extent, and in some instances fils intervene between the exposures of the rocky beds. These drift deposits a greatly in thickness; nature of materials of which they are composed, and narder of arrangement of these materials; therefore, it is almost impossible » nd two sections of drift beds that will agree in every particular. Prof. r>n speaks of the drift in the following language:

"Before describing the leading characteristics of these beds, it will be ier to call attention to an interesting fact that must be referred to the ur agencies by which the drift itself is explained. Considerable portions of u -ocky surf ace of the county have been planed, polished, striated and grooved y eavy masses of ice - inclosing sand, gravel and bowlders - moving over in. These phenomena can be best observed in the firmer beds of the i ;ara limestone, occupying as they do the highest table lands of the county, alley are by no means confined to them. The great belt of quarries southif; of Dayton furnish fine exhibitions of this agency. Indeed, these naturally laed surfaces are frequently turned to account for door-steps, flagging stones lcother similar uses. It is altogether probable that the whole surface of the tij.ty has been exposed to the abrading agencies of the glacial sheet, as we lithe marks of these agencies at every point where the rocks are firm enough tain them. The unconsolidated beds of the Niagara rocks have been in ri measure removed by the same force that has planed the harder surfaces, s evident from an inspection of those .higher portions of the system that ii yellow clays intermingled with gravel and bowlders. Sometimes heavy : u itic blocks have been left in the clay in almost immediate contact with the a< ed rock, their own surfaces having been planed and scored by the service > rich they have been put. We see in them the implements of abrasion - hmgraving tools - left where the work was done. The thickness of these a deposits varies from one foot to thirty feet, and the upper portions are r 'st always freer from gravel than the lower portions. Occasionally a lime-; deposit of blue clay is found on the surface of the rocks, but for the most : u these beds of blue clay, when they occur, are found overlying yellow clays ' Ids of gravel, in pockets of small extent. Fragments of drifted coniferous a 1 are sometimes found buried deep in these deposits. Next in importance e yellow clays are the beds of sand and gravel, of which the drift beds f argelv composed. They sometimes overlie the clays, are sometimes inter - r hied with them, and sometimes they repose directly upon the surface of k ocks. The gravel contains representatives of all the formations that are ad to the northward within the limits of the State, viz., blue limestone, '-Ron, Niagara, water lime, coniferous and black slates, and a considerable 31 of it is derived from the metamorphic rocks of the Lake Superior region and °i ids Canadian highlands. To the same source must be referred the sand, ' :> silicious formation of any considerable extent occurs between these de- 1 W.s and the line of the great lakes. The sand and gravel have a thickness - !: least 100 feet in many instances. The deposits are always distinctly r died, and exhibit many alternations of fine and coarse materials that bel"l;i considerable changes in the conditions of their formation. Thoy often show, especially in the beds that occupy the lower levels of the county, beat structure, or marks of the action of water that could only be impressed ap< them while they lay at or near the surface. The sand and gravel are som times cemented into massive blocks by the deposition of carbonate of lime fre the spring water that Hows over and through them. Recourse was former had to these cong-lomerates for building stone, but it was found that they we worthless for such purposes, as they cannot withstand the action of frost.

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

Building Rock. - The thi'ee rock formations exposed in Montgome County furnish abundant material for this use. " The blue limestone affon in numberless exposures, a building stone that is accessible, easily quarrie even bedded, of convenient thickness and very durable. It possesses, howev but little susceptibility of ornamentation. The thinness of its beds, its bar ness and brittleness, stand in the way of its impi'ovement by dressing, and color is too dark to please the eye when it is exposed in large surfaces of m sonry. The Clinton rock, in all of its beds - but especially in its upper ones affords a building stone that would be highly valued were it not for the clo proximity, in most instances, of the quai'ries of the Niagara group. A simil statement can be made in regard to the products of the blue limestone quarri of the county. When the Clinton stone is first raised from the quarry, it frequently so soft as to be easily worked; but when the water has escaped fre it, it becomes a measurably firm and enduring stone. Some of its beds, i deed, are crystalline, or semi-crystalline in structure, and leave nothing to desired as far as durability is concei'ned. As already remarked, the Clinti group exhibits a great variety of colors, and some of these shades are ve pleasing to the eye - a fact which makes this stone susceptible of fine arehitei ura I effects. The greatest objection to this series is that it is not genera! even-bedded. The lower strata are very seldom so. The Niagara group, ho ever, furnishes the best building stone, not only of Montgomery County, but the whole Miami Yalley as well. Indeed, for many piu'poses it is inferior none. Occurring as it does, in even-bedded layers of from four to twen inches in thickness, it is adapted to the purposes of both light and heavy m sonry. It is homogeneous in structure, has a beautiful color, takes ornamenl tion quite kindly and is durable to any required degree. The value that attached to it can be judged from the fact that in some of the quarries nean to Dayton, the stone sells in the ground for $17.50 per rod, or $2,800 per ac: the title to the land not being alienated. In these quai'ries there is less tin five feet of workable stone, and this can only be reached by removing from fi to twenty feet of drift clays and sands. * * The supply of the rock even this, its best estate, is inexhaustible, but the expense of transportation sin out at present from the general market all the quarries that are more th three or four miles distant from Dayton. The quarries that lie outside these limits, however, are invaluable for neighborhood supplies. The quali of the stone, when perfect in every other respects, is sometimes injured by t

" In addition to the kind of rock already named, there is in the county a - ire supply of Niagara rock that falls short of the typical excellence in hard- -,i3 and color, but which still constitutes a very serviceable and valuable dejit. These beds of inferior quality are sometimes the precise stratigraphical Avalents of the true Dayton stones; that is, they immediately overlie the iton formation, but generally they occur at a higher level in the series, ri differences in color and hardness alluded to seem connected with differ - ,]jea in chemical composition, the Dayton stone being a nearly pure carbonate ntime, while the inferior grades are composed of the carbonates of lime and Limesia. The color of these last-named beds is not constant, various shades jllrab and yellow alternating with shades of blue, sometimes even in the same [{far of rock. In durability they seem in no way inferior to the standard [Mon stone. The bowlders of the drift are also available for building purp|es. They form, in some parts of the county, the main supply for founda -ills, and, when treated with skill, give excellent results."

Brick. Draining-Tile and Pottery Clays. - Outside of the alluvial bottoms, nrly every section of the county furnishes, from its drift beds, material from vch brick can be manufactured, the yellow clays overlying the Niagara rock : lithe higher table lands being by far the best for the purpose. In many '333, the walls of a building can be constructed of bricks of the best quality njle from the clay taken from its site. " Beds of blue clay are also abundant, c erally at lower levels of the county, from which draining-tile and pottery c: be made. For these purposes, the blue and yellow clays are generally a:;ed, the blue clay imparting the necessary strength and the yellow countering the tendency of the former to shrink and crack in the process of baking. Te importance of drain-tile in agriculture begins to be understood. Hun- 1 Is of thousands of tiles are now manufactured annually, with a steadily ini.asing demand. A third variety of clay is found within the county, in quite lilted deposits compared with the preceding. It also is called blue clay, but differs from the ordinary blue clay in containing no iron. It is converted b; burning into a cream-colored brick of the same general character as the V waukee brick. It is generally very fine grained, and has been quite largely u d as mineral paint. In composition, it consists of little besides alumina, -iica and lime. There is no doubt that these deposits will be regarded with oreasing interest, as their advantages for architectural purposes come to be cognized. The heaviest accumulation of this clay now known in Southern C io occurs near Springfield, Clark County, and it has already been turned to g k! account in the manufacture of Milwaukee brick.

" Firestone . - -A stone that can endure the action of heat, admits of many nful applications. Two of the bedded rocks of the county have considerable l|al reputation as firestones, viz. , the sandy limestones that make the upper - nst beds of the blue limestone series and the Clinton group. This latter rk certainly answers a tolerable purpose for chimney jambs and kindred il is. It is not easy to see what there is in its composition that enables it to f ist unchanged the agency of fire, as analyses show it to be a true limestone i' a good degree of purity. Experience, however, abundantly demonstrates its vue in this regard. Chimney- jambs can be shown that have stood over fifty ) its in service. Farmers are willing to transport it for miles to lay up the aihes of their sugar camps. It must be added that the different beds of the sues have very different qualities in this respect, the middle and lower layers l nishing the best firestone, and there is no doubt that the quality in its highest 1 -fibition is local.

man art, the sources of its supply are of more economical value to any comm nity than are the supplies of building stone and brick clay even. All the be ded rocks of the Miami Valley, and portions of the drift as well, furni materials from which excellent lime can be made. It is needful, however remark that the terms limestone and lime do not convey any precise infora tion as to the chemical composition of the substances to which they areapplii Limestones always contain carbonate of lime, it is true; but besides this th generally contain various compounds and various proportions of ma^nes alumina (clay), silica (sand) and iron. The limestones of this region that c be burned into valuable lime may be divided into two classes, according their chemical composition. The first group comprises those rocks that cons mainly of carbonate of lime, or that contain at least 85 per cent of this su stance. The second group is made up of the dolomites, or magnesian lin stones, which have at least 40 per cent, of carbonate of magnesia in their co position. Silica, alumina and iron are found in small and varving prop( tions in each division. The properties of these limes are very difforei Those of the first class require to be submitted to a higher temperature burning than the second. They slake promptly and thoroughly, and in t operation evolve a great degree of heat. From this last fact they are term 'hot' or 'fiery' limes. They 'set' or harden so soon that but two or tin bricks can be laid with one spreading of mortar, and walls that are made them have a tendency to 'chip-crack.' It is quite likely that, this last ram property can be attributed in some degree to the silica and alumina which th contain. The second group contains those limes that are called 'cool.' Th do not give out so much heat in slaking as the limes of the first class, nor they 'set' as soon. From five to twenty bricks can be laid with a sing spreading of mortar, and in plastering a corresponding advantage can be c tained. On purely practical grounds, the builders of Southwestern Ohio ha come to recognize the greater desirability of the limes of the last-named ola and none others can now find a market in the cities and towns of this portij of the State. To the first series belong the blue limestones, the Clinton gro and the Dayton beds of the Niagara group. The limes of the second sen are all obtained from the upper or Niagara division of the cliff limestones, a; the kinds of rocks from which they are derived constitute almost the ent; mass of this formation. It thus appears that the Niagara group in Ohio is true magnesian limestone, as all the members of this same great series throng out its wide western expansion - in Michigan, Wisconsin, Illinois, Iowa a: Minnesota - have uniformly been found to be. The only exception to lh< statements as to the composition of the Niagara series is found in some of i lowermost beds, where in limited and isolated areas the Dayton stone and : equivalents occur. This stone has already been referred to the true limeskms an analysis of it made by Dr. Locke, in 1835, showing that it contains 92 p cent of carbonate of lime. While with this exception the whole Niagara sorij consists of magnesian limestones, it would be wrong to conclude that eve portion of this series, taken indifferently, can be burned into valuable lin The quarries that are worked for lime burning at Cedarville. Yellow, Spring Sprin glield, Moore's quarries below Springfield, Wilson's quarries north i Dayton, and a few others less widely known, furnish the most valuable lire of the Miami Valleys and largely supply the markets of Cincinnati, Daytc Hamilton, Springfield, Xenia and the remaining towns and villages of this sc tion. These quarries all lie in the same geological horizon, viz., between 1 and 100 feet above the base of the Niagara rocks. They begin in or above tl strata that contain the large shell Pentamerous oblongus, and generally inclui from ten to twenty feet that overlie the Pentamerous beds - a series of thin ai irregularly bedded strata, valueless for building stone., largely filled with i il fragments. The strata that underlie the Pentamerous beds consist of , ,jl anrl drab magnesian limestones, which cannot be burned into a good artiibf common lime, but which there is good reason to believe possess in greater rjss degree the properties of hydraulic cement or water lime. A sample r,ji the quarries of W. Sroufe, Esq., Yellow Springs, when analyzed, was o id to agree very closely with a magnesian limestone of France that is cited yificat as an excellent hydraulic cement. The same rock, when treated in iiratory experiments, indicates an eminent degree of hydraulic energy."

" Mineral Paints. - The materials from which mineral paints have been aufactured in this portion of the State are all obtained from the beds of ci . The second variety of blue clay, already described, is principally used /this purpose." A company was organized at Miamisburg about 1867 or St , and their sales, in 1869, aggregated over 100,000 pounds, which included ciisiderable portion of lead. " The bed of clay which is turned to most acn|t is situated on Hole's Creek, at no great elevation above the Miami River, h clay is identical in composition with the heavy bank near Springfield, and tolly resembles the 'Milwaukee brick' clay in composition." An analysis of Hole's Creek clay is herewith presented:

." Many of the gravel beds of the drift contain accumulations of ocher o or less extensive, and occasionally deposits of the same substance are ul unmixed with gravel. The ocher can be separated from the gravel by tiling, and proves to be of fair quality. A large deposit of this ocherous ad is to be found on the north bank of Twin Creek, one mile east of Gert. own. Montgomery County. * * A bed of brown coal, that occurs in t ame gravel bank, has been turned to account for the manufacture of black -i . Mastodon remains and phosphate of iron are found also in this locality. a]|jag all things into account, no more interesting section of the drift is to und in this region than the ' Germantown ocher bank. '

Gravel. - It is not easy to set a proper estimate upon the beds of sand '(gravel of the county until a comparison is instituted between a region well I- iod with such accumulations and another which is destitute of them. The a 1 knolls and ridges with which, in the southern and eastern portions of e county, almost every farm abounds, afford very desirable building sites. Are generally selected for such purposes. Sand of the best quality for orjir, cement and brick making, is everywhere within easy access. An inexaijible supply of excellent materials for road-making - what is frequently deseed 'clean limestone gravel,' though in reality largely composed of granitic : kl.es - is found in the drift deposits, from which hundreds of miles of turniv k have been already constructed in the county, thus affording free communi- 1 til between farm and market at all seasons of the year. The smaller bowl- Hori of Canadian origin, are selected from the gravel banks for paving-stones, rua ^ted to the neighboring cities. In regions where stone suitable for ai iamized pikes can be obtained, good roads can be had, even though gravel is wanting, but at largely increased expense above that of gravel turnpike The districts which are supplied with neither can certainly never compete i desirability with these gravel-strewn regions.

" The agricultural relations of the different formations of Montoumei County remain to be briefly discussed. Only those points will be touched upc which are especially noticeable. From what has been already said of the dii tribution of the drift, it may b8 inferred that this formation will conceal or ol scure all the rest, and, to a considerable extent, this will be found to bo tl case. There are large areas in which the underlying rock seems to have i direct effect upon the superficial beds, further than to control the general fea ure of their arrangement. In such cases the soil depends directly upon tl composition of the drift beds, and will be found light, warm and dry, heavy, cold and wet, according as sand or clay predominates in these bee There are, however, several varieties of soil that receive their leading chara teristics directly from the rock with which they are associated. The hi', table lands of the Niagara limestone, which are mostly confined to the northe portions of the county, furnish the first example. These limestones are oft covered with but a shallow deposit of clay, yellow originally, but blackened ! organic matter for a foot or two from the surface. These table lands hold nearly a horizontal position that the streams that have their sources in the have but a sluggish flow. Indeed, these districts, until they are cleared ai ditched, are almost always marshy in their conditions, and, though occupy in the highest level of the county, are universally spoken of as low-lying land I They contain abundant elements of agricultural wealth, but demand a mo| painstaking and scientific kind of treatment than our farmers are genera willing to bestow. In default of this, they are largely dependent on thestl sons - favorable seasons bringing a large reward and unfavorable ones bei marked by failures more or less complete. The water supply in these lot tions is generally derived from drilled wells, which it is sometimes necesssj to carry to a depth of sixty feet, though one-third of this depth usually suffia-j In their present condition they constitute the lowest-priced lands of the coun unless, as in a few instances, their contiguity to markets has led to their thij ough improvement. In these cases, they show themselves to be possessed' admirable qualities for farming lands, and also give examples of what may j hoped for from the remainder of this formation. A belt of still more p; nounced character, in which the agricultural relations are still more closj! connected with the geological structure, is furnished in the line of junction the blue limestone and Clinton formations, or, what is the same thing, in I line of junction of the Lower and Upper Silurian.

" It will be remembered that the uppermost beds of the blue limesti series consist, for the most part, of unconsolidated clays, while the lower p tion of the overlying cliff formation, viz., the Clinton rock, is largely ec posed of beds of a porous sandstone (lime sand). The result of this order sequence is that the clays of the blue limestone series are the water fijearert the region which they occupy, as was long ago pointed out by Dr, Loc The strongest springs of Southwestern Ohio mark quite accurately7 this liny junction. The clays constitute a gradual slope - sometimes one-fonrih oji mile in breadth - from the foot of the cliff. The springs that flow oat ahjj; the line gave, before the country was cleared, a marshy character to this b as is shown in the black and fertile loam by which it is still marked. T also serve to distribute, to some degree, the waste of the cliff to the slope be!

"The early settlers located their hoines iD the vicinity of these perenr springs, and the prosperity which has attended che labor of husbandry u; these fruitful tracts is well attested in the comfortable and tasteful hoi!1 which mark the lowermost outcrop of the cliff limestones. Perhaps no ot a logical boundary of the State is so definitely connected with human interests. jV) blue limestones give rise, in limited areas, to soils of great fertility. The pflrq of this age, for the most part, are covered deep by beds of modified [ft, lying as they do at a lower level than the other rocks of the county; but opsionally, a slope is found that is derived directly from the weathering of ,i blue limestone bods. The rocks of this series are rich in phosphates, a which accounts for their value in agriculture. An analysis by Dr Wormi chemist of the survey, give sixteen-hundredths of 1 per cent of phosphoric id in the bedded clays. This proportion shows that a soil one foot in depth, rued from the weathering of these clays, would contain to the acre very prly 7,500 pounds of phosphoric acid - a substance indispensable to the rwth of the higher forms of vegetation. The celebrated blue grass country Kentucky is derived directly from the rocks of this formation, without the , lition of our drift clays and sands.

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

"Attention will be called to but one more point in this connection: The ripr valleys of Southwestern Ohio are known to have been deeper than they a:l at present. In other words, they are now partly filled with drift, and the mams no longer flow upon rocky beds. Not only is the absolute depth of I valleys diminished by these deposits, but the abruptness of the declivity greatly modified by them. Instead of a precipitous descent over the naked e|es of the rocks, a well-graded slope, consisting frequently of the best road gjvel, leads from the highlands to the river bottoms. The nature and order o the succession of the formations previously described, renders it certain fit were it not for the interposition of the drift, the line of junction of the b e limestone and cliff formation would be an impassable belt of miry clay for op- third of the year, unless relieved by expensive artificial roads. A similar site of things would be found throughout much of the blue limestone regions. Is leading points in the geology of the line of junction of the Lower and ITpp Silurian formations of Southwestern Ohio have now been briefly noticed. v * Among the points of economical interest may be mentioned the estab- Inment of the limits within which the Dayton stone is to be found, lying as it d|s at the very base of the Niagara series; the recognition of the fact that the

1 the series than that which the Dayton stone occupies, with the consequent kpwledge of the areas within which it occurs, and the discovery that certain els of the same series afford hydraulic lime of excellent quality. The great ' ue of the Dayton stone naturally leads to considerable interest in the disci ery of new deposits of it. A safe guide for all future investigations will be f ind in the order of sequence of the great formations, an order which pract'al men, engaged for years in quarrying the stone, hare generally failed to rognize."

An extensive bed of peat was discovered, some years since, one mile east cj Germantown, Montgomery County, in and directly above the channel of bin Creek, of which a very interesting account is given in the appendix to. L reports of the Ohio geological survey of 1869. This volume may be found 8:Ong the books of reference in the public library at Dayton, and to it we ' uld refer all interested, as it is not thought best to extend this chapter to {eater length.