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Introduction
In order that the general reader may the better understand the following chapters, a brief Introduction to the general physiographic and geologic conditions of the state may not be out of order. Kansas is a part of the great plain stretching from the Mississippi river on the east to the Rocky Mountains on the west. It is approximately 200 by 400 miles in extent, and should be looked upon as a block in the great plain, constituting an essential part of it but not specially different from other portions lying on either side of it. The elevation above sea level of the eastern end averages about 850 feet, with Bonita 1,075 feet, about the highest point, and Kansas City 750 feet at the Union depot, the lowest. The north and south boundaries have approximately the same elevation, although the increase in height is more rapid along the northern side from the Missouri river westward, while on the southern side the rapid increase in height does not begin until farther west. The lowest part of the state is the Verdigris river valley where it crosses the southern line. At the Missouri Pacific depot in Coffeyville the elevation is 734 feet, 16 feet below the Union depot at Kansas City. The southern line crosses the great ridge west of Independence, the Flint Hills, which lifts the elevation to over 1,700 feet, but it again declines westwards towards the Arkansas river to an elevation of only 1,066 feet at the Santa Fe depot in Arkansas City, From here to the southwest corner of the state the ascent is gradual, increasing slightly with the distance, so that for the western hundred miles across the whole of the state the eastern descent is from 7 to 12 feet to the mile. The western boundary line varies slightly from north to south but is close to 4,000 feet above sea level, sometimes being slightly more and again a little less.
The drainage of the state is therefore to the east. Here and there an irregularity of surface will deflect the stream southeast or south, as the Verdigris river aud the Blue river, or northeast, as with the Republican river through a part of its course, and the lesser tributaries to the Missouri in the northeastern part of the state. The streams usually have a considerable current due to the great incline of the surface as a whole which, from west to east, averages nearly eight feet to the mile for the whole state. Towards the eastern part of the state they have broad and level valleys filled in to from 20 to 60 feet with alluvial material, while in the far west some of them have scarcely reached base level.
The general physiographic conditions of the state are not as regular as is usually supposed. Although the surface is a great plain sloping eastward, its minuter topography is often varied and rugged; valleys 200 feet deep, bluffs and mounds with precipitous walls 300 feet high, overhanging rocky ledges, and remnants of cataracts and falls in numerous streams giving a variety of scenery, are to be observed almost all over the eastern part of the state, and to even a greater extent in some parts of the west. The physiography of a country is dependent upon its geologic structure, so that we may begin physiography by a study of structural geology.
The geologic structure of Kansas, when considered on a grand scale, is simple, but in detail often becomes complex and difficult. In the extreme southeast part of the state over an area not exceeding 30 square miles, dense limestones and interbedded chert rocks, with the residual products produced by their superficial decay, constitute all that is to be seen of the geologic formation. These limestones and cherts extend westward as far as prospecting with the drill has yet shown their presence or absence, constituting the floor upon which rest all of the remaining parts of the rock formations of the state. Could we examine below this floor we would find that it in turn rests on other rocky layers and they on others for a distance of about 2,000 feet, at which place the penetrating drill would reach the solid granite or gneiss or schist below which no limestones or sandstones or shales could be found. But the limestone and flint beds above mentioned are the floor for the Kansas formations, and may well serve as a limit to our present investigations. In the eastern part of the state this floor universally dips to the west, the southwest or northwest, varying in places to a considerable extent, but being moderately uniform, and the superimposed strata one above the other follow this inclination. This westward dip of the strata, and the eastward dip of the surface serve to bring the succeeding strata individually to the surface like the ends of shingles in the house roof. As we pass westward the surface rises from the horizon but rises doubly fast from the limestone and cherty floor, so that could we dig a trench from the eastern line of the state westward following the surface of the floor, it would rapidly become deeper and in its walls would be exposed the successive layers of rock one above the other as they actually occur. But the westward sloping of the strata is not continued throughout the whole state. Scarcely has one-third of the distance been passed until the order is reversed. The eastern part has been influenced by the great inland swell of the Mississippi valley, the Ozark Hills, while the western part has been more mightily influenced by the great Rocky Mountain uplift, Could we continue our trench westward to the western side of the state we might find that the limestone and cherty floor extended that far, but most probably long before that distance was reached it would pass into rocks of other character. Of this matter, however, we are in total ignorance, as no boring has yet been put down deep enough to throw any light on the subject; but the lines of stratification marked on the walls of our trench would change their direction and incline eastward instead of westward.
The different rocky strata now found lying one above another were formed' at different times. It is desira-ble as a matter of convenience. to assign names to the different time periods and to the different great divisions of the rock strata in order that we may converse intelligently about them. In the history of the rise of the science of geology we find different customs have been followed at different times and by different people, so that there has not been a perfect uniformity in the choosing of names for time periods or for rock formations. But as the science grows older this disparagement of usage will gradually grow less. In 1889 the United States Geological Survey [Tenth Annual Report, Director U. S. Geol. Surv., p. 65; Washington, 1890] decided upon a certain series of names to be given to the great time periods, which in general correspond with the usages of standard textbook makers, but which, in, a few particulars, differ somewhat from that usually observed in other publications. They divided all geologic time into 11 periods and gave the following names and limitations:
"The first (the latest) period shall cover the time beginning with the first ice invasion and continuing until the present, or that which is commonly called the Quaternary.": This was called the Pleistocene.
"The second period shall include the time divisions sometimes called Pliocene and Miocene, Its earlier delimitation shall be that indicated by paleontology, and its latter the first ice invasion of the Pleistocene; and its designation shall be Neocene."
"The third period shall be the Eocene. . . . Its definition shall be that commonly accepted by paleontologists and geologists as determined by fossil remains."
"The fourth period shall be the Cretaceous. Its definition shall be that indicated by paleontology and usually accepted."
"The fifth period shall include the time divisions known as Jurassic and Triassic, and shall be designated Jura-Trias, Its definition shall be by paleontology."
"The sixth period shall be Carboniferous, including the subdivision sometimes called Permian, Its definition shall be by paleontology,"
"The seventh period shall be the Devonian. Its definition shall be that indicated by paleontology and usually accepted."
"The eighth period shall include the time divisions sometimes styled Upper Silurian and Lower Silurian and otherwise styled Silurian and Ordovician. Its definition shall be by paleontology, and its designation shall be Silurian."
"The ninth period shall be designated the Cambrian. The definitions of its upper limit shall be by paleontology. . . . Its lower delimitation shall be the time of deposition of the lowest rocks thus far known to yield a well defined fauna."
"The tenth period shall be the time of deposition of plastic rocks older than the Cambrian. . . . ."
The eleventh: "The oldest time division shall cover the time of formation of the ancient crystalline rocks, and its designation shall be Archaean."
Of the above mentioned geological column, Kansas geology deals only with the Carboniferous and younger rocks excepting as we may penetrate far below the surface of the earth by drill or imagination to consider those which lie beneath the great floor already mentioned. The portion of the column above the Devonian is well represented in our state. The little corner of crystalline limestone and chert in the southeast part of the state represents the lowest member of the Carboniferous, which was formerly called the Sub-Carboniferous, but for which term Mississippian as suggested by Williams [Williams: U. S. Geol. Surv., Bul. 80, p, 135; Washington, 1891] has come into general use. Above; the Coal Measures proper are developed to a thickness of from 2,500 to 2,750 feet, and thePermian to the thickness of 795 feet, Above the Carboniferous, over portions of the state, a small amount of Jura-Trias is found, while the Cretaceous is extensively developed over more than one-third of the state. Still above the Cretaceous, in the western part. Covering an area equalling nearly one-fourth of the state, a heterogeneous deposit of sand, gravel, clay, soil and other loose materials occur in great abundance. This has generally been called the Teritary, yet it may yield to subdivision into the Eocene and Neocene to conform with the classification above quoted. In the northeastern part of the state are extensive deposits of the glacial drift material which constitutes an important part of the Pleistocene, and again in the Tertiary area of the west the looser sands and gravels have unmistakably been worked over and modified in recent times, and soils and gravels have accumulated over other parts of the state, so that the Pleistocene formations practically mantle the whole of our area. As this report is confined entirely to the different members of the Carboniferous formations, no attention will-be given to the minuter classifications of the formations above it, while the subdivisions of the Carboniferous will be given in the body of the report.
As the Carboniferous rocks are composed of alternating beds of limestones and shales, the latter of which frequently grade into sandstone, it has been deemed advisable in making the drawings for the plates illustrating the great sections, run in different directions, to insert nothing but the limestones, leaving the blank spaces between for the shale beds with their included sandstones. The limestones are extensive and persistent, and may well be likened to great shelves placed one above another in the underlying portions of our state. Could one transform the shale beds and sandstones into a transparent medium, by standing near the southeast corner of the state and looking to the northwest one could see the limestone shelves reaching far back to the west dipping gently in the direction they extend dividing the volume considered into stratum above stratum of relatively thick shales and sandstones separated by the thinner limestones which, here and there, increase to double the normal thickness, but which have great lateral extent and are remarkably even and regular in comparison with their length and breadth. The eastern limit of these several shelves would gradually progress westward from the bottom upwards. Were the surface uniform the limits or the outcroppings would be parallel lines. But with the river valleys cut deep into the surface and the high mounds and table lands constituting the ridges, it will readily be seen how the eastern limit of each individual shelf must necessarily be a sinuous line, each, while trending from northeast to southwest, may be exceedingly uneven in direction. Wherever the limestone is reached, however, a greater or less escarpment is produced by the wearing away of the softer shales beneath, the height of which is usually dependent upon the thickness of the shale beds. When those become thinner, that is, when the shelves in our model approach closer together, the escarpment becomes less and usually the outcropping is carried farther to the east; for the weathering agents can wear away a thick bed of shale that is capped with limestone more readily than it can a thin one. If we travel from the east towards the west, therefore, we are constantly passing upwards from one shelf to another, from one escarpment to another, with the limestone shelves lying on top of each other. On the map, plate XXXI, an attempt has been made to represent this condition, by giving a semi-perspective view of the block, Kansas, of the great Mississippian plan. On the south and east vertical walls are represented on which are traced the sections of the walls with the several lime, stone shelves above mentioned. On the surface. of the map the southeastern outcropping of the same shelves are marked and the irregularities in the lines are produced as above explained, while when they approach nearer together it is always due to a thinning out of the shale bed between the two limestone shelves.
It has been thought best to give individually an account of the conditions observed along each line of section so that the reader may see and handle the evidence upon which the greater conclusions rest which will be brought in after these several detailed descriptions are given.
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Kansas Geological Survey, Geology
Placed on web June 1, 2017; originally published 1896.
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