Madison County, Illinois - Chapter 4: Geology of Madisox Couytt, 1882

Chapter 4: Geology of Madisox Couytt

HE geology of this county may be illustrated by the following section, taken principally from the exposures of the strata along the bluffs of the Mississippi river, where it forms the boundary line of the county of the west.

This system is by far the most important geological formation in the State, since it determines in a large degree, the character of the soils which forms the materia! wealth of Illinois.

The Quaternary iu Midison county may be divided into three distinct deposits; tha Alluvium or bjttom deposits, the Loess, and the true drift of the glacial age. The alluvial is the most recent.

The great American Bottom is largely alluvial, although there is reason to suspect that this great basin was once filled with true drift clays which have since been much modified by the overflowing floods of the Mississippi and Missouri rivers. This bottom commences, a short distance below Alton near where Wood river emerges from the highlands. Here the harder limestones of the sub-carboniferous dip beneath the surfice give place to the coal measures. The softer shales, sandstones and limestones of the coal measures being more easily exoded away, give the valley of the Mississippi here a wide expanse. In Madison county this bottom is some ten miles in width, and comprising something over one hundred sections or square miles, a majority of which are among the richest lands in the United States. Originally a larger portion of this was a kind of bottom prairie on which flourished an enormous growth of wild grasses. The higher portions of this bottom, and this includes the greater part, are now mostly under cultivation producing quantities of market produce, such as potatoes, cabbage, &c. Good crops of both corn and wheat are raised, but much of the land, especially near St. Louis, is too valuable to be planted in these cereals Much of the land does not overflow, while the lower portions, are being rapidly brought under cultivation by being drained and protected by levees.

The geological character of the subsoil of this region is peculiar, being in some place a sandy or gravely strata, alternating with layers of silt and a black vegetable mould, some of which has the consistency of putty, and goes by the name of sticky; at other places the deposits seem to be a yellowish or brownish clay resembling glacial deposits.

The sands and silt from the Missouri river are different from those of the Mississippi, and these deposits are sometimes seen in contrast in the bottom.

The thickness of these alluvial deposits are not known, but a boring at the National stock yards in East St. Louis failed to reach the bottom of the deposits at the depth of one hundred feet.

Loess

The loess usually present a finely comminuted mass of siliciuos marly clay, and is easily recognized by its buff color and general appearance. Above Wood river and the city of Alton, it forms the earthy deposits which cap the blufls. Below AVood river the bluffs bordering the bottom are almost entirely of loess. It sometimes goes by the name of "Bluff clays," from the fact that it is only seen in the vicinity of rivers, and its presence is probably due to the silty clay deposits during the subsidence of the glacial epoch, when the great sluggish streams at the close of that era were confined to the valleys. This subsidence was doubtless of slow continuance for the deposits in this county are in some places more than a hundred feet in thickness. The loess extend but a few miles from the river and the more tenacious clays of the drift take its place.

The rich character of the farming lands about Edwardsville, and all the high lands in the vicinity of the bluffs are due to the marly character of the loess which form the subsoil. The recuperative power of such soils even when apparently exhausted is remarkable; a few crops of clover restores the weakened energies of these lands to their original vigor. The loess contain both land and fresh water shells and sometimes the remains of extinct animals, generally of the larger mammals. Near Alton, some years ago was found some remains of a mastodon ; we also have the tooth of an extinct bison, and an undescribed mammal from this region a few miles above Alton.

Drift

The true drift clays which cover the rocks on the high lands are quite different from either of the divisions of the formation we have described. The drift clays were no doubt accumulated when the whole surface was under water, and the rocks being in places eroded into valleys which more subsequently filled with these drift clays. They are much deeper in some localities than others, although the surface level may be the same. There is usually at the base of this depo3it a blue plastic clay, with pebbles, and oftentimes are found in it sticks and even the bodies of trees, with pieces of coal and other accumulations; sometimes the blue clay is wanting, but above it is generally a reddish brown clay with boulders and fragments of rocks that do not belong even in the State. These foreign substances seem to have been brought here in icebergs, or floating masses of ice and earth, which melting, the hard material with the clay was deposited on the bottom. Often in digging wells these drifted materials are met with to the wonder of those not conversant with the manner of their disposition. Sometimes valuable minerals are found in small quantities, leading the unwary to suppose a mine is near.

The next system beneath the Quaternary in IMadison county is the carboniferous or coal measures. The coal veins that crop out in this county belong to what is known as the lower coal measurt-s. This county being on the edge or rim of the great coal basin, besides having its strata elevated and cast off by an upheaval of the rocks, has the outcropping edges of the coal formation, as seen here and there at various localities, weathered and broken, so peculiarly situated as to render it difficult to make a correct section. We know of no shaft or boring that has penetrated I the whole series of the carboniferous in the eastern side of the county where they probably all lie in place. A thin seam of coal at Highland probably represents No. 8 or 9 of the general section of the state. There are probably five distinct coal seams worked in the county. Coal seam No. 1, which is worked about North Alton, seems to have local dimensions that have created some confusion in numbering the veins in this locality.

The best seam of coal on the eastern side of the county, and known as the Bellville seam, we are inclined to believe, notwithstanding previous reports, to be No. 5, the main workable seam of the state.

Most of the coal mined in the county is of good quality. The coal taken from vein No. 1 at Buckin and vicinity we consider au excellent coal and of much superior quality to that taken from No. 5 at Virden, 111., and vicinity.

Excepting a strip of land along the Mississippi river, above the city of Alton, nearly the whole county is underlaid with valuable beds of coal. There are in the county some 250,000 acres of good coal lands. Considering the easy access to this great store of wealth, and its accessibility to the leading railroads of the state and St. Louis as well as the Mississippi, Madison is most enviably situated in this respect.

According to the report of the mine inspector of Madison county for the past year we learn that there are 27 mines in the county, all being worked by shafts ana affording employment to 1000 men and boys. The yearly product is 400,000 tons, and the capital invested 248,000 dollars.

Chester Lime.Stone

Immediately underlying the coal in this county, in some localities, is the Chester limestone. The Chester group of the subcarboniferous is several hundred feet in thickness in Randolph county, but has thinned so rapidly towards the north as to be represented in Madison by only some twelve or fifteen feet in thickness. It is a coarse-grained sandstone of a brownish color and overlaid by a thin baud of limestone two to three feet in thickness.

St. Louis Limestone

The most important rock in Madison county is the limestone, known as the St. Louis limestone, which forms a bluff something over one hundred feet in height, and extending from the city of Alton to the mouth of the Piasa creek.

During the disposition of this group of rocks on the bottom of that ancient sea one is forcibly struck with the different conditions of the elements during this great subcarboniferous era, as the following section will show:

The upper beds thin out rapidly above Alton, and the group ascends to the top of the bluff' at the Piasa, giving place to the Keokuk group which come up from beneath the Mississippi.

It makes a valuable cement, and ought to be among the great resources and industries of the country. The rock is a bluish gray, earthy Magnesian limestone, sometimes a delicate dove color, quite soft and very easy to quarry.

Hitherto the heat in the kilns required to reduce this rock to lime preparatory to grinding into the cement flour, has been made with wood. The nearness of the coal mines and the cheapness of this fuel might be brought into requisition in the manufacture of the cement. Situated as these cement deposits are, on the banks of the Mississippi and near the coal mines, ought to give them a commercial value.

The upper members of the St. Louis limestone, so finely exposed at Alton, furnish some of the finest building materials in the state. There are layers in the quarries of Alton of hard, compact limestone that would make a building as durable, and of richer, finer appearance than the Magnesian limestone of Jolietor Grafton. The pure color of this freestone is very pleasing to the eye and is retained without change for a great length of time.

When monotonous brick walls and perishable frame buildings give way to solid structures of architectural beauty the materials in these great quarries of Alton will be in large demand.

Besides being used as a building rock the St. Louis limestone is the main source of the supply of lime in the west. It makes a beautiful white lime, not more noted for its color than its strength.

There is, probably, no place in the west where could be found the same facilities for the manufacture of superior lime as at Alton. There is an unlimited supply both of fuel and material for lime.

The means of shipping both by rail and river are excellent. AH that is needed is enterprise and capital to make its manufacture at Alton a great industry.

The fossils of the St. Louis limestone are quite numerous about Alton, and some of them are very finely preserved. There are several species of productus, the more common of which is the P. Punctatus, and one pretty species called P. Allonensis. Spysipers and Terebratulas are common. About the bluffs can be found fine specimens of that pecular coral, like a mass of columns, and known as the Liihostrot'ton Canaden.se and just above the beds of hydraulic limestone the pretty pentrineites are common, and in some of the lower layers of the group above the city of Alton, numerous fish teeth are found. About the little village of Clifton, near the mouth of the Piasa, fossils are numerous.

Keokuk Limestone

The lowest rock exposed in this county belongs to the group known as the Keokuk limestone. It is represented in several localities on the Piasa creek by 20 to 40 feet of a shaly calcareous lira33torie of m ecimmic valu3.*

There are but few counties in the state favored with the natural resources and elements of wealth and pro.sperity for its inhabitants enjoyed by Madison county.

It possesses a soil of unsurpassed fertility, an excellent supply of timber, an inexhaustible supply of coal, buildingstone, limestone for lime, cement and potters' clay, with a favorable position on the Mississippi; together with railroad facilities and other natural advantages seldom found.

Artesian Wells

In the economic geology of Madison county, the subject of artesian wells may interest many. The conditions necessary for a successful artesian well are very simple.

1st. There must be a stratum of porous rock or other substance beneath the surface forming a conductor for water; this conductor being usually sand or sandstone.

2d. The source of the supply of water must be higher, or as high as the surface of the proposed well. Very often it happens, however, that the force of pressure or the presence of gas, forces the water in an artesian well above its source.

The source of the supply may be, and often is, many miles distant. It is said that the source of the water flowing from the artesian wells in Chicago is in the outcropping sandstones on Fox River nearly a hundred miles distant. The source of the supply of water in the Belcher well in St. Louis is in the outcropping sandstones in Calhoun County, 111.

Nearly all the artesian wells in this State, and in fact in this part of the Mississippi Valley, get their supply of water from soft heavy bedded sandstone, known to western geologists as the St. Peter's sandstone.

Through the agency of some subterranean power, evidently of a volcanic nature, the St. Peter's sandstone, the lowest rock seen in Illinois, is upheaved and brought to the surface, forming a high bluff'on the bank of the Mississippi at "Cap au Oris," (Grey - sandstone headland) in Calhoun County, Ills., and nearly forty miles northwest of Alton. This sandstone forms part of the bed of the Mississippi at this place. The headland or Ijluff", is something over a mile in extent along the river, and near 200 feet in height. Much of this rock is so friable as to be crushed between the fingers, and such pure silica as to be in demand in the manufacture of glass.

'Cap au Gris' being the centre of the upheaval, except, on the southwest where the deposits seem not to have been thrown up, the rocks dip strongly in going from the axi.s. The upheaval of the St. Peter's of course brought up all the rocks lying above it, but this great elevation being afterward eroded away by the forces of the "glacial epoch," a general level was again attained leaving the outcropping edges of the Upper Silurian, Lower Silurian, Devonian, Subcarbonifer. ous, and coal measure rocks exposed in succession to the view of the observing traveller in any direction on the line of Cap au Grig.

In all this western country there is not such another field for the study of geology. Every stream, or water course in Madison, Jersey and Calhoun counties reveal the edges of the rocky strata, each group of which can be recognized by its peculiar fossils; and each group of which can be measured, at least approximately, so that any competent geologist at any point within fifty, or even a hundred miles from Cap au Gris, can tell very nearly how far beneath the surface lies the St. Peter's sandstone, down through the heavy beds of which percolate a portion of the waters of the Mississippi.

The following diagram will enable the reader more fully to comprehend the geology of this region. The diagram represents a section of the rocks from Edwardsville on a straight line to Cap au Gris :

The horizontal stratum on top of the section represents the drift-clays that overlie all the rocks except where washed away in the valleys formed by streams Below the drift which is 20 to 100 feet in thickness the rocks are represented showing their position and dip. No. 1, crops out at Cap au Gris, No. 10, at Edwardsville. We give iu the table below

The thickness here given is mostly taken from the exposed strata along the Missi.ssippi, some places being covered on the slopes by debris are supplied by better sections of the same horizon as shown in the creeks and smaller streams. The thickness, however, we believe to be given as the maximum.

Seven or eight miles north of Cap au Gris, on the Mississippi side of Calhoun Co , is an arte.-ian well 200 feet deep, and from which a great volume of water has been flowing for over thirty years. This well is represented on the left of the diagram near Pittsburg, in Jersey county, or some 15 miles east of Cap au Gris is another well, started in the Devonian, and which reached a great flow of water in the St. Peters, at the depth of 500 feet. This well was bored several years ago with the view of finding coal oil, and is 825 feet deep. It is a sulphur water, containing some minerals in solu. tion, not unpleasant to the taste, as may be evinced by the fact that a graduating class of 1.3 young ladies visiting the locality under our charge drank heartily from the water as it flowed over the tube. Without doubt it could be utilized for nearly all mechanical purposes.

The waters of Perry Springs, in Pike county. 111., noted as a health resort, is somewhat similar, and is doubtless nothing more than a natural artesian well, in which the waters from the St. Peters escapes to the surface through some crevice. In our opinion many of the so called mineral springs have the same deep-seated source, and might be duplicated without number by simply going deep to the St. Peters sandstone with an artesian well and making an artificial spring.

An artesian well in Madison county is simply a matter of dollars and cents. The water bearing strata lies beneath with the great probability of its treasures being released only by the drill.