fully investigated, but is known to lie unconformably upon the upper Coal-measure rocks of that region, and is suspected to be a part of the Dakota group of Cretaceous rocks, and therefore of Mesozoic age. The disappearance of the upper members of the Madison county section is of course most rapid to the eastward and northward, because the drainage, as well as the borders of the formation are in those directions. They are all found exposed on Clanton's fork of Middle river, as far southward as the village of Peru, but the next exposure of rocks to the southward is on the Missouri river water-shed, and belongs to the carbo-argillaceous horizon before referred to; but its bed of coal does not appear so far eastward. This is the most northerly exposure of rocks on Grand river, and is ten miles from the one last mentioned, and five miles eastward from Afton, the county seat of Union county. Fossils are numerous here in the thin calcareous bands between the layers of carbonaceous and argillaceous shales; lamellibranchiates and gasteropods predominating. Although a hundred miles eastward from Nebraska City, it is unmistakably of the same horizon as division "C" of Prof. Marcou's section there (loc. cit.), as shown by the identity and association of fossils at both localities, as well as by their stratigraphical relations. Following down Grand river the stream is found to have a fall amounting to a little more than the general dip of the strata, and consequently makes its exit from the state with its bed in the representative of No. 15 of the Madison county section. Immediately westward from Winterset the upper beds also disappear, but somewhat less rapidly. The first good exposure in that direction, after leaving Middle river at the west line of Madison county, is on the East Nishnabotany river, some forty miles distant; yet so simple is the geology of this region that no hesitation is felt in referring the strata there to about the horizon of Nos. 8, 9 and 10 of the preceding section, particularly since that view is corroborated by observations on intervening ground to the southward. The next important * * Of the sixty-three species described and identified from division "C" of Prof. Marcou's section at Nebraska City by Dr. Geinitz, twenty six are lamellibranchiates, and thirteen are gasteropods, which two classes of Mollusks contain the types which are principally relied upon by those gentlemen to prove the Permian age of the rocks at Nebraska City. I'regret that I cannot fully agree with Dr. Geinitz in his identification of genera and species, yet I have been able to distinguish of those described and identified by him from that division, twenty species of those lamellibranchiates, and nearly half of those gasteropods, in the above named beds on Grand river; which beds are certainly not above the middle of the upper Coalmeasure series as developed near the middle of the state. I moreover find that those lamellibranchiates and gasteropods with other species, characterize the horizon before referred to; the import of which is conceived to be that when they lived, they found there a congenial habitat, and not that the Permian period then and there commenced. exposure in that direction is near Crescent City, a few miles above Council Bluffs, and is referred to about the horizon of No. 13 of the same section. Thus it will be seen that the line of strike is practically east and west between Madison county and the Missouri river. It was remarked that the fall of Grand river is a little greater than the southerly dip of the strata over which it passes, so that one finds lower beds exposed as he goes down the stream. This would be expected from the fact that the stream bears a little to the eastward, obliquely across a slight westerly as well as southerly dip; but the fall of all those streams between that, and the Nishnabotany river, is almost exactly coincident with the dip of the strata, wherever they have cut their valleys through the heavy drift deposit. This is clearly seen along the Nodaway river, where the bed of coal of the horizon before referred to, reaches its greatest development, and is found a little above the water at intervals, from the northern part of Adams county, to a point a few miles within the state of Missouri. The impure limestones associated with the coal bed, along the course of this river and its branches contain, both above and below the coal, but more especially below it, very many species of fossils identical with those at the locality on Grand river just referred to, and also with those at Nebraska City, which Dr. Geinitz and Prof. Marcou refer to the Permian period. (loc. cit.) No other rocks except those of this horizon appear along the Nodaway, but the Tarkeo has bared the equivalent of No. 15 of the previous section, in the northern part of Page county, as has also the East Nishnabotany, in Montgomery county. The lower part of the carbo-argillaceous horizon is occasionally seen in the valley slopes of those two streams, but its bed of coal is not seen west of the Nodaway, until the bluffs of the Missouri river are reached in the northwestern part of Fremont county, at the locality before mentioned, where the coal has diminished in thickness to six inches. The same bed of coal also dimin ishes in thickness as one goes down the Nodaway, being found only ten inches thick just within the state of Missouri; and to the eastward it thins out entirely before reaching Grand, or Middle river. The following section was measured in Fremont county at the base of the bluffs, twelve miles northeastward from Nebraska City. It is numbered from the top downward and designated as the Compact gray limestone, No. 10. Light yellow indurated marl, No. 11. Yellowish siliceous limestone with flinty masses, No. 12. Yellowish earthy shale with concretionary layers of limestone, No. 13. Compact, gray limestone, No. 14. Yellowish earthy shale, No. 15. Heavy bedded limestone, with dull fracture, No. 16. Bluish shale, No. 17. Soft, yellowish siliceous stone, crowded with Fusulina, 1“ 16 4 2 66 4 No. 22. Bluish, thin-bedded, fine-grained, micaceous sandstone, 1 66 The localities of the two sections here given are nearly one hundred miles apart, yet their equivalencies are very satisfactorily determined. No. 22 of the Fremont county section is regarded as equivalent with No. 15 of the preceding one; and the remainder of the Fremont county section, as equivalent with that portion of the preceding one between the lower portion of No. 6, and the top of No. 15. No. 7 of the Madison county section is regarded as equivalent with Nos. 2 and 3 of that of Fremont county, both belonging to the carbo-argillaceous horizon before described. Beneath this horizon, and more or less associated with it, there is quite a definite Fusulina horizon, which forms a conspicuous stratigraphical feature in the southwestern counties, but since these fossils range through the entire upper series they cannot always be relied upon for strati graphical determinations. It is quite otherwise, however, with the horizon first named, for we are able to recognize this, with more or less certainty all over the region in question, both by its bed of coal, or carbonaceous character where that does not exist, and also by its peculiar paleontological features. The subject may be briefly summed up thus: 1. Besides the usual paleontological and lithological differences between the Coal-measure rocks and those beneath them, there seems to be in Iowa almost an entire absence of magnesia in the former rocks, while it prevails so largely in those of older date.. 2. The lower Coal-measures contain nearly all the coal of the state, and are composed principally of sandstones and shales. 3. The lower Coal-measures alone are found along the DesMoines river, and to the northward and eastward of it. 4. The upper Coal-measures lie wholly to the southward and westward of that river, the receding borders of that formation resting conformably upon the lower series. Consequently the rocks of the upper series do not reach the border of the Coalfield, nor do they ever lap upon the rocks of older date than the lower Coal-measures, as they are supposed to do in Illinois. 5. The region more particularly described in this article is comprised within that portion of the three southern tiers of counties lying between the Missouri river, and a line running southward from the city of Des Moines. 6. The rocks of this region belong principally to the upper Coal-measures, which are seen resting upon the lower Coalmeasures at the eastern border. 7. A few beds of the upper series thin out, but no true unconformability is recognized. 8. The upper series is believed to contain but one bed of coal, properly speaking, the maximum thickness of which is twenty inches, and its greatest development along the Nodaway river. 9. The stratigraphy of the whole region is very simple, the line of strike being practically east and west, and the dip, to the southward nearly coincident with the fall of the streams. 10. The highest Paleozoic beds are to be found in Madison county and belong to the upper Coal-measures. 11. The lowest beds exposed along the Missouri river, or upon its water-shed within the region herein described, belong also to the upper Coal-measures as designated on the previous pages. 12. No Subcarboniferous rocks are found westward from the immediate vicinity of the DesMoines river. 13. There is a definite carbo-argillaceous horizon recognized over the greater part of this region which is characterized by the bed of coal before referred to, and in the strata of which lamellibranchiates and gasteropods prevail, and sometimes predominate. 14. Above this horizon as well as below it, characteristic upper Coal-measure brachiopods, and other fossils prevail. 15. Below this horizon the rocks increase in thickness and calcareous character from east to west, and probably also to the southward. 16. Nishnabotany sandstone occurs in the counties of Mills, Montgomery, Cass and Pottowatamie. It lies unconformably upon the upper Coal-measure rocks, and is supposed to be of Cretaceous age. Iowa City, Iowa, March 27th, 1867. ART. III.-Notes on the Geology of Kansas;* by F. V. HAYDEN. PERHAPS few portions of the globe of the same size have furnished more facts and collections of interest to scientific men, both in Geology and Paleontology, than those drained by the Missouri river and its tributaries. Since 1853 the greater part of my time has been devoted to the development of the geology and natural history of this great region. During that period I have personally examined the greater part of the territories of Kansas, of Nebraska, Dakota, Montana, Idaho and Colorado, and it is but natural that I should read with great care and interest a publication on the geology of any portion of that country emanating from any other source. It was on this account that an official report on the Geology of Kansas by Prof. Swallow was hailed with pleasure. In the summer of 1858 Mr. Meek and the writer made a careful examination of a large portion of Kansas from Leavenworth City westward to Smoky Hill, and the results of that exploration were published in the Proceedings of the Academy of Natural Sciences at Philadelphia, Jan. 1859. In that paper opinions were advanced in regard to the relations of the Permian to the Carboniferous rocks which were accepted by most of the geologists in this country and in Europe. In the report of Prof. Swallow, however, opinions have been expressed on some points opposite to those in the paper above referred to, and it is the object of this article to pass these opinions under review. Mr. Meek has furnished some carefully prepared notes which form the substance of this article. Although Prof. Swallow acknowledges (p. 43) that these Permian strata (his Lower Permian) graduate into, and are so nearly conformable to, the Coal-measures below, that "no want of conformability can be detected by examining any one locality, though the line of junction be traced a long distance;" "Yet," he continues, "when sections are made across the line of junction at distant points, it becomes evident that there is a striking non-conformability. When the sections made across this line on the Kansas, at Manhattan and above, are compared with those on the Blue, though separated by several miles, there is no difficulty in identifying all the important strata in one with those of the others; and when these sections are compared with those at Mill Creek, some 25 miles east, and with those on the Cottonwood, 60 miles south from Manhattan, the prominent beds are easily identified down to the lowest of the Permian, No. 84 of the above section; but Nos. 85-95 from the section near Manhattan are not found, when No. 84 rests directly down Preliminary Report of the Geological Survey of Kansas. By G. C. SWALLOW, State Geologist. Printed at Lawrence, Kansas, 1866. |