THE PLAINS PROVINCE 93 



"These long stretches of sandstone extend from just west of Pawnee, nearly 

 straight south to the vicinity of Shawnee, a distance of 60 miles on an air-line. 

 Wherever the region of shales west of this belt was crossed, as near Lela, west of 

 Stillwater, Goodnight, etc., another belt of thickened sandstones was found. 

 Another feature of this region that must not be lost sight of is the fact that the 

 lower horizons traced eastward grade out into normal light-colored beds of 

 marine origin, at least nearly as far south as Shawnee. Whether these great 

 masses of sand were thrown up as barriers along the southern tongue of the sea to 

 the north and northeast, or whether they represent river debouchures from the 

 mountains to the southward has not yet been determined. For a number of 

 reasons, some of which will follow, the writer is at present inclined to the opinion 

 that they are connected with rivers. With further work it appears now that the 

 question can be settled quite definitely and the origin of the sediments deter- 

 mined. If they were barriers, it would seem peculiar that the different layers 

 should thicken and thin so nearly simultaneously, while this is what would be 

 expected if the sand were brought down to mouths of rivers whose channels at 

 times extended well out across low fans, coastal plains, and shallow waters. 



"In some places the deposition of sandstone is very irregular. Over some 

 areas a sandstone may be wanting and its place apparently filled with soft shales 

 that weather and slump very rapidly, forming great amphitheaters. In some 

 instances the sandstones occupy beds cut in the soft shales by currents of some 

 kind. * * * 



"Many of the peculiarities which have been described occur in the northern 

 part of the State. Farther south, and especially farther west, they appear to be 

 more complicated. Another feature that was noted was that some of the beds 

 became quite coarse by the time the latitude of Shawnee was reached. Our 

 studies did not extend south of Shawnee. 



"The fact that the stratigraphy is more regular in the same horizons in the 

 eastern part of the region studied than in their western extensions, as well as the 

 fact that the same formations contained limestones with marine fossils at their 

 eastern outcrop for some distance south of Pawnee, would seem to indicate that 

 an arm of the sea at Neva time extended south from the great northern area as 

 far as the Cimarron River, or a little beyond, but that its waters were extremely 

 shallow, if present, on the flats west of the 96° 45' meridian. The disappearance 

 of the fossils and the irregular and interrupted character of the stratification 

 seems to indicate the passing from marine conditions on the northeast to shallow 

 water or even subaerial conditions to the south and west. This would appear 

 to be the direct result of the influence of the Arbuckle Mountain region upon the 

 sedimentation of the time. Subaerial conditions continued near the mountains 

 and marine conditions beyond the influence of its fans." 



B. THE LATE PALEOZOIC IN OKLAHOMA. 



The relation of the vertebrate-bearing horizons of the Texas and Okla- 

 homa red beds to the Kansas limestones and shales is not and probably can 

 not be exactly determined from the very nature of the deposits. Some few 

 beds have been traced by Adams and Beede directly into Oklahoma, where 

 they shade off into red shales and sandstones, but they are not vertebrate- 



