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Show 213 bases are of the Niobrara. Farther west it forms the whole of the visible outcrop, and the mounds are not so prominent. On Prairie Dog Creek, in Norton County, it is 400 feet in thickness, and in the extreme northwestern part of the State we have reason to believe it is still thicker. The various strata are not clearly defined or regular in line of deposit, and the continued thickness cannot be easily discovered. The formation, like all others iu the State, appears to dip I slightly to the northwest It is conformably, or nearly so, upon the Cretaceous. In the southern portion of the Pliocene, in the vicinity of Fort Wallace and Sheridan, the hill- tops are covered with a stratum about 8 feet in thickness, very hard and siliceous. The material varies from coarse flint- quartz to chalcedony. The latter mineral shades from milk- white to transparent, sometimes presenting a semi- opal appearance. The so-called moss agate is found in the upper few inches of the stratum. Over a considerable portion of the Pliocene no fossils are to be seen; ; but at other points they are somewhat abundant. They are of modern tvpe, represented by bones of deer, beaver, a large animal of the ox ! kind, two species of the horse, less in size than small Indian ponies, a I wolf, ivory from the elephant or mastodon, bones of the rhinoceros and | camel, and also remains of undertermined character. In addition to | these mammalia, we find the bones and carapace of a large fresh- water | turtle 5 feet in length. All the bones are firmly fossilized, and most of them changed to a bard, compact silica. The most interesting of these is the ivory. In the process of petrifaction^ the tusk must have been so softened as to admit the intermixture of black oxide of manganese in solution, which then crystallized in delicate sprigs. The ivory was next silicified into nearly pure quartz, with the usual hardness of that substance. Thus we have the ivory converted into the so- called moss agate. Some fragments could not be detected, by the ordinary observer, from the usual specimens of that gem. This ivory is found in fragments in the extreme upper portion of the deposit, and we were at first inclined to call it Post- Tertiary; but the peculiar fossilization, similar to some of the other bones, induces me to think that it belongs to the close of the Pliocene. The remains of the horse are apparently the most common, the teeth and jaws being found from Smith County to the vicinity of Ellis, in Ellis County. One is a species of the celebrated three- toed horse, having three hoofs coming to the ground. In the northern part of Ellis Coanty, our party, in 1875, fouud the feet, with the three toes in excellent preservation. Iu most cases the bones are badly broken, and much of the skeleton missing. A full and careful examination of the Pliocene of Kansas will undoubtedly furnish some valuable fossils, illustrating the mammalia of the period, and give to science some new species. The Eocene and Miocene have not yet been discovered in Kansas, unless tbe specimen of the three- toed horse, found in Ellis County, should prove to be the Anchitherium of the Miocene. It was imbedded in the lowest part of the deposit, within 10 feet of the Niobrara lime-stoue. Further examination of this formation is desirable. No. 3 2 |