These two groups may be described together, as there is no line of division, either by physical deposits or fossils. The line of division between the Carboniferous and the Cretaceous is as described in the Dakota. The deposits consist of limestones, clay shales, sandstone, and, in the upper portions, gypsum and chert beds. In the lower strata the limestones are more compact and uniform, and the chert beds less numerous. Some of the lime has been called magnesian, but analysis has failed to show, in more than a single instance, over five per cent. of magnesia. In most strata they afford, on being burnt, a good quick lime. The shales - sometimes improperly called slate, and sometimes soapstone*** - are all in some degree composed of lime, so that of the whole deposit fully one-third is made up of that substance.
*** There is no slate or soapstone in Kansas. They both belong to Metamorphic rocks, of which we have not a single bed.
The strata of this period, like those of all before described, are nearly horizontal, but dipping slightly to the northwest, and are of nearly the same persistence and regularity over a large extent of the outcroppings. The exceptions to the tendency to dip to the northwest are distinctly to be seen in some instances. Thus the peculiar and clearly defined black shale, with its contiguous firm limestone, seen near the Penitentiary, south of Leavenworth, dips easterly, and appears at the water's edge of the Missouri river, at Parkville. A similar instance occurs in the heavy bed of limestone in the bluffs, in the southern part of Wyandotte county.
No metallic mineral, except poor iron, and that in small quantities, has yet been found in the area covered by the Upper Carboniferous, and the geological indications strongly discourage any attempt to search for them. The deposits are so clearly undisturbed, oceanic and sedimentary, that metallic substances can not be expected.
The Upper Carboniferous, with the Permian, forms the surface strata over an area of nearly twenty thousand square miles. The outline can be traced by reference to our geological map. The total thickness is not far from two thousand feet.
The fossils of the Permian, whether we include four hundred or eight hundred feet of the Upper Carboniferous deposits, are represented very largely by marine mollusks and corals, usually in good preservation.
These represent in a good degree the ordinary Carboniferous species of persistent forms, and of wide geological range. Intermingled with these in the higher strata are species having a general complexion similar to the Permian of Europe. But there are some of the species quoted by Dana from Meek and Hayden, as characteristic of the true Permian, which are seen as far down as the Coal Measures, Prof. O. St. John and myself have found them (such as Pseudomonotis Hawnii, Myalina perattenuata, Pleurophorus, Subcuneatus, etc.,) around Topeka, and I understand he has taken them in even lower strata. The higher strata have more of the Permian types, and they steadily decrease as we go downward. Dana adds: "Among the species of mollusks, from the beds referred to the Permian by Swallow, seventy-five in number, nine-tenths occur also in the Carboniferous beds below."*
* Manual, page 368.
Atrilobite - Phillipsia - is found nearly to the top of the Permian.
Plants are scarce, consisting of some fucoid and a small quantity of poorly preserved land vegetation. Like the Permian of Europe, it furnishes no coal.
Other portions of the Upper Carboniferous contain more land plants, and, in a few instances, as we shall describe under Economical Geology, a few thin seams of coal. The whole may properly be called barren Carboniferous. Borings, five or even seven hundred feet, have been made in this area without reaching any good workable seam of coal, and none outcrops near the surface.
