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Geological Survey of Kansas, v. 2 (1897)

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Introduction to Kansas Geology

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 hight is more rapid along the northern side from the Missouri river westward, while on the southern side the rapid increase in hight 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 1700 feet, but it again declines westward toward the Arkansas river to an elevation of only 1066 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 seven to twelve feet to the mile. The western boundary line varies slightly from north to south, but is between 3500 and 4000 feet above sea level.

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 and 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. Toward the east part of the state they have broad and level valleys filled in for from 20 to no 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, over hanging 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 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 rocky portions of the earth accessible to the student of geology are confined to the surface of the sphere. Mountain chains are elevated, deep gorges and river channels are worn, and vast faults, or dislocations, are made in various places, whereby the rocky strata are exposed so that an accurate knowledge can be gained of the surface to considerable depth provided the field of observation is sufficiently extended. It is now generally understood that the oldest rocks of the globe are massive in form and crystalline in structure. It is probable they represent the oldest parts of the earth which is exposed to view anywhere upon its surface. It is likewise probable there was a time in the early history of the earth when the ocean waters entirely covered the whole surface of the sphere. Subsequent irregularities of the surface were produced by a contraction of the volume of the earth and portions of the ocean bottoms were lifted into dry land. No sooner was this accomplished than the ordinary agents of destruction and decay everywhere present in the atmosphere began acting upon these freshly exposed surfaces and resulted in wearing vast quantities of them away and carrying them back into the ocean by the drainage which resulted from the rainfall. In this way sedimentary material was produced which, added to the various forms of sediment already existing in the ocean bottom produced layer upon layer of material over different parts of the ocean bottom which ultimately became changed into one kind or another of rock.

As the contraction of the diameter of the earth continued, and probably is in progress even at the present time, the irregularities in the surface were correspondingly intensified. The valleys in the ocean bottom were made lower and lower and the valleys between the dry land uplands were likewise made more intense, so that the difference in elevation between the land areas and the water areas was constantly increasing. But the destructive agencies of the atmosphere were likewise active upon all the dry land as fast as it appeared above the ocean water and constantly larger quantities of sediment were carried from the dry land back into the ocean. In this way the superficial portions of the globe were constantly being worked over and spread out over the ocean bottom in the form of relatively thin coverings of stratified rock in which layer upon layer of first one kind of material and then another was produced.

At the present time the greater portion of all of the dry land of the globe is covered with stratified rocks thus produced. The remaining part is covered with rocks resulting from one form or another of volcanic action or, in rare cases, possible of a portion of the original dry land materials is preserved.

The stratified rock, therefore, should be looked upon as relatively thin layers of sediments that have been accumulated and which have as great diversity of character as corresponds with the different conditions under which they were formed. Some of them are composed principally of grains of sand weakly or strongly cemented together, producing the different kinds of sandstone. Others are products of the finer sediments, the material which was carried in such large quantities into the ocean from the dry lands. These are usually designated by the one term shale, with explanatory terms prefixed as occasion may require, such as clay, or argillaceous shales, sandy, or arenaceous shales, bituminous, or carbonaceous shales, etc. A third kind of stratified rock which is everywhere present is produced by the accumulation of the shells of the various forms of marine invertebrates and is known by the general term of limestone. Here likewise various explanatory terms are employed to specify in greater detail the particular character of the limestone. In this way the whole of the stratified rocks of the earth may be classed under the three general heads of sandstone, shale, and limestone.

These various forms of material are interbedded with each other, sometimes in a very intricate manner, but usually in such forms that their relations to each other can be easily understood by those who are trained in field work in geology. The surface of the globe in anyone particular place rarely exhibits more than one or two or possibly three of the various forms of rock just described, but by traveling some distance in any direction others are usually reached which overlie or underlie the ones first examined. The different strata in this way are brought to the surface so that they can be examined. Passing under each other in whatever direction is necessary for a particular place, the strata are found in positions somewhat similar to the position occupied by the shingles on a roof.

The time occupied in the formation of each of these stratified rocks has been very long, has included almost all the time generally understood as geologic history. For convenience and simplicity of expression it is desirable to refer to the various time epochs during which different rock strata were being formed, and correspondingly refer to the rocks produced during such time epoch.

In the history of the rise of the science of geology we find that different customs have been followed at different times and by different people, so that there has not heen 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. Geological Survey, 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 text book makers, but which, in a few particulars, differ somewhat from that usually observed in other publications. They divided all geologic time into eleven 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, for 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 limitations shall be that indicated by paleontology, and its latter the first ice invasion of the Pleistocene; and its designation shall be the Neocene."
"The third period shall be the Eocene. . . . ts 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 as 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 term Algonquin was mentioned and agreed to as the designation of the period."
"The eleventh: The oldest time division shall cover the time of formation of the ancient crystalline rocks, and its designation shall be Archaean."

From what has already been said the reader will understand that it is impossible at anyone place to find all the geologic horizons. There are different points in America from which one may start and travel over the exposed edges of the successive formations throughout a considerable portion of the entire column.

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 surface. The portion of the column above the Devonian is well represented in our state.

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 thirty 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 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 2000 feet, at which place the 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 on 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 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, 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.

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Kansas Geological Survey, Geology
Placed on web Jan. 20, 2018; originally published 1897.
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