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Part I—Stratigraphy of the Kansas Coal Measures
By Erasmus Haworth
The stratigraphy of the Kansas Coal Measures has been partly described in many publications. Volume I of this Survey contains the longest connected description thus far published. That description was based principally upon field work done by this Survey, but was looked upon as being elementary in character. For that reason, and in, order that the reader might the better judge of the correctness of conclusions subsequently drawn, a number of geologic sections trending mainly east and west were, in the early chapters of the discussion, described in detail by the parties making them. Field work in stratigraphy has been carried on to a considerable extent for each of the past five seasons. This has enabled us at present to give a tolerably detailed and connected description of the stratigraphy of the Kansas. Coal Measures; While it will largely be a reproduction of that already published in Volume I it will also be a correction and confirmation of the same.
The Kansas Coal Measures rest on a floor of the Subcarboniferous limestone .. This has been observed to be true throughout the whole of the eastern limit of the Coal Measures and has been proved to be true throughout all of the western part wherever wells have been drilled deep enough to penetrate the Coal Measures. The description of the Coal Measures proper may, therefore, begin with a description of the Subcarboniferous floor, after which the various subdivisions of the Coal Measures will be taken up in the order in which they are found in the ascending scale. While studying the descriptions of them the reader should refer constantly to the generalized section, Plate VI, and to the various other maps and sections illustrating them.
I—The Mississippian or Subcarboniferous
Areal Extent
The area in Kansas covered by the Mississippian rocks is confined to the southeastern corner of the southeastern county. It is bounded on the south by the south line of the state; on the east by the east line of the state; and on the northwest by an irregular line trending northeast and southwest, crossing the south line of the state near Baxter Springs about six miles from the Missouri line, and the east line of the state about ten miles from the southeast corner, forming a triangle of about forty-five square miles, with the northwestern boundary approximately marked by Spring river.
In different places the western limit is carried beyond Spring river, particularly where tributaries enter from the northwest. These streams have worn their channels down through the overlying Coal Measures and have exposed the Mississippian for some distance further to the northwest. Along Cow creek, for example, the Mississippian rocks may be observed more than five miles above the general limit; along Shawnee creek they may be observed almost to opposite Crestline, three or four miles beyond the general boundary; along Brush creek the westward dentation is not so marked; while along Wall creek the western limit is two or three miles beyond the boundary. A few places are known beyond this limit where erosion has worn away the overlying Coal Measures exposing the Mississippian to the surface. This is particularly marked in what is, now called Quaker Valley, to the northwest of the country postoffice Tehama. Here within five miles of the center of the county an area of several acres is covered principally with the Mississippian limestone and flint rocks, existing as an isolated outlying area, separated from the main body of the Mississippian by four or five miles.
Beyond the limits of Kansas the Mississippian occupies the surface over a large part of Missouri on the east, Arkansas on the southeast, and Indian Territory on the south, It forms, in Missouri, an irregular area extending east about thirty-five miles to beyond Springfield; to the northeast by way of Carthage, Stockton, Osceola, Sibley, Boonville, and Keatsville to beyond the Missouri river, from which point it veers eastward to the vicinity of Saint Louis, thence northwestward along the Mississippi river into Iowa. It occupies all of the northwestern part of Arkansas and the northeastern part of the Indian Territory, constituting a large area of well defined rocks of great thickness which must always be looked upon as one of the most important terranes of the great Mississippi Valley.
Surface of the Mississippian
The surface of the Mississippian limestone in some places was greatly eroded during the pre-Coal Measure time. This has been commented upon by various geologists, has been illustrated by drawings and photographs by different authors, and varied and important conclusions have been drawn from such effects. The writer has already described various irregularities of surface in southeastern Cherokee county, which are probably due to this surface erosion (Haworth, 1883; Haworth, 1884; Haworth, 1895; Haworth, 1896b; Hay, 1893). The extent of such erosion farther to the northwest can only be conjectured, as the surface of the Mississippian soon becomes covered to a great depth with the overlying Coal Measures. The records of the various oil and gas wells in Kansas which have been carefully kept and accurately tabulated fail to show any marked irregularity of surface. This of itself is not conclusive, for the wells are not close enough together to disprove the existence of valleys of erosion in the surface of the Mississippian; however, with so many of them reaching the Mississippian limestones and at so nearly uniform and regular distances below the surface it is moderately certain no very great irregularity can exist on the upper surface of these limestones.
The importance of this question is connected principally with a study of shore lines during geologic time. The Mississippian rocks were formed under ocean water. Where the surfaces are eroded they were of coarse subsequently elevated above the ocean water and thereby the ocean shores receded to the west. Later, when the Coal Measures were laid down, covering eroded surfaces, the shore lines again migrated eastward. If, during the erosion period, the shore line migrated very far to the west the eroded area likewise will extend farther west. But if, on the other hand, the eroded area forms a narrow stretch extending along the southeastern limit of the Coal Measures as we now find them, then the shore line immediately previous to Coal Measure time did not progress very far to the west. This latter condition seems to have prevailed.
The extent of erosion in Kansas, as far as is known, is not very great, and therefore does not imply a very long period between Subcarboniferous and Coal Measure time. There is a perfect conformity between the Coal Measure strata and the upper surface of the Mississippian in Kansas when viewed over wide areas, as is clearly shown by the geologic sections published in Volume I, and those which accompany this report. If, therefore, there were any considerable oscillations after the Mississippian limestones were formed and previous to Coal Measure time it is remarkable that the final state of equilibrium reached and maintained during the earlier part of Coal Measure time should place the surface of the Mississippian in a position so that no broad nonconformities should be produced. These conditions indicate, therefore, that the oscillations which resulted in leaving the Mississippian rocks above the sea and in again depressing them so they could be covered by Coal Measure strata were confined to slight vertical movements and to narrow limits along the coastal area, movements which did not materially affect the same rocks further oceanward.
Inclination of Surface
The tipper surface of the Mississippian floor dips to the west and northwest. Along the southern line of the state from, Galena to Coffeyville the maximum dip is not known, as no well at Coffeyville has thus far reached the Mississippian. Wells have been drilled from 550 to 600 feet and have not reached it. As the elevation of Coffeyville is 728 feet above sea level and the hill tops at Galena something over 1,000 feet and the distance between the two points fifty-three miles, we know that the inclination westward is at least 17 feet to. the mile. By an examination of the geologic section from Galena westward by way of Cherryvale, Plate I, it will be seen that we have the surface of the Mississippian at Oswego about 400 feet above sea level, which would give the inclination from. Galena to Oswego at about 20 feet to the mile. Wells at Stover and Mound Valley do not reach the Mississippian, but at Cherryvale, fifty miles away, it was reached at 1,008 feet below the surface, or 180 feet below sea level, which gives the decline of the surface from the hill tops at Galena at about 22 feet to the mile, or but a little over 20 feet to the mile if reckoned from the valleys about Galena. The deep well at Neodesha shows substantially the same results. The deep wells farther west in the vicinity of Fall river, Fredonia, Wichita, and other places throw little light on the subject as they do not reach the Mississippian, but their great depth without reaching it shows that it must occupy a position similar to that indicated from the dip further east.
In a direction northwest from Galena the inclination of the surface of the Mississippian is not so great. A well made with a diamond drill, producing a core, at Saint Paul—Osage Mission—thirty-nine miles northwest from Galena, went to a depth of 700 feet without reaching the Mississippian. The elevation of Saint Paul above sea level is 873 feet, showing that the Mississippian is at least within 173 feet of sea level and that its surface has a dip from Galena of not less than 21 feet to the mile. At Chanute, fifty-eight miles away, it was reached 36 feet below sea level, and at a few other points in that vicinity at similar depths. The decline from Galena to Chanute towards the northwest is therefore between 17 and 18 feet to the mile.
Northward, along the east line of Kansas, the inclination is much less. The Mississippian is reached at Girard at 493 feet above the sea level, at Fort Scott at 385, at Pleasanton at 206 feet above sea level, and at Kansas City at sea level. The inclination from Galena to Girard therefore is about 16 feet to the mile; from Galena to Fort Scott between 11 and 12 feet to the mile; the inclination from Galena to Pleasanton between 10 and 11 feet to the mile; and from Galena to Kansas City between 7 and 8 feet to the mile. The direction from Galena to Kansas City, by way of Girard, Fort Scott, and Pleasanton, makes It sharp angle with the line of the southeastern limit of the Coal Measures or the northwestern margin of the Mississippian area.
Lines in a direction more nearly at right angles with this northeastern and southwestern trend would probably show a greater dip to the apparent surface of the Mississippian. East of Fort Scott the Mississippian is reached about twelve miles beyond Nevada, Mo., or thirty-one miles from Fort Scott. Along this line the upper surface of the Mississippian dips westward between 14 and 15 feet to the mile. Fifty-four miles eastward from Pleasanton the Mississippian comes to the surface a little beyond Brownington, at an elevation of about 760 feet above sea level, which gives a dip of between 10 and 11 feet to the mile. Sixty-three miles to the southeast of Kansas City the Mississippian appears at the surface in the vicinity of Sweet Springs, which would give it an inclination towards Kansas City of about 15 feet to the mile. Westward from Kansas City it has not been reached in any of the deep wells. The well at Topeka reached a depth of over 1,600 feet; which shows that the Mississippian inclines not less than fourteen feet to the mile for that distance. The McFarland well, of over 2,000 feet, likewise shows that the inclination must be as great as 13 feet to the mile to that point.
We may conclude, therefore, from the above data, that along the southern line of Kansas the Mississippian floor declines more rapidly to the west than in any other direction, where it; has an inclination of more than 20 feet to the mile; that to the northwest from Galena, by way of Saint Paul and Chanute, the inclination is considerable less, reaching but 17 feet; and that the westward inclination from other points further north is less than the westward inclination from Galena. These conclusions are important and are in accord with the detailed stratigraphy of the Coal Measures which overlie them, all of which show that. there was an extraordinary thickening of deposits along the southern line of Kansas which thinned both eastward and northward to near the middle line of the state, and which again thickened northward. There seems to be a slight ridge in the Mississippian floor trending east and west and passing through the middle part of the state, probably by way of Pleasanton, and reaching to an unknown distance to the west.
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Kansas Geological Survey, Geology
Placed on web Sept. 12, 2018; originally published 1898.
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