GEOLOGY AND PALEONTOLOGY. 55 
Park mountains (see map, p. 54). From this section it will be seen that within 
the Ozark uplift is a core of archean rocks which are exposed within limited 
areas in southeastern Missouri. Around this core is an area of the older Palzo- 
zoic formations. Passing westward, we find the beveled edges of the later 
Paleozoic formations. Along the line of the section they are represented as 
- follows: First, undifferentiated Cambrian and Silurian and the Subcarboniferous. 
Within the prairie plains region lies the Carboniferous. The Arkaneas plateau 
region embraces the Permian, the Red Beds (which are referred by some to the 
Permian and by others to the Triassic), the Comanche, Dakota, Benton, and 
Niobrara; while resting unconformably upon these is an irregular deposit of the 
Tertiary. At the base of the Park mountains are the upturned edges of the 
Cretaceous and older rocks, while within the region the formations are much 
disturbed and the ranges contain eruptive and archean elements. Kansas may 
be said to be an area of slight disturbance lying between two mountainous 
regions, whose complex histories have produced simple oscillations over the 
regions of the prairie plains and the Arkansas plateaus. 
We cannot reconstruct with much certainty the original areas of these various 
formations, but they once extended much further to the east; and to produce 
their present surface and beveled outcrops, erosion has been at work at varying 
intervals and for long periods. The westward dips and the succession from older 
to newer formations along this section argues in favor of the hypothesis that the 
shore line during Paleozoic times was to the east. This hypothesis is still fur- 
ther strengthened by the fact that the deposits themselves, show marginal con- 
ditions in their eastern outcrops, while the records of deep wells show deep-sea 
conditions to have been more prevalent to the west, as is indicated by the thin- 
ning of shale beds and the thickening of the limestone systems. 
That this shore-line made many oscillations and migrations is evidenced from 
the alternation of oceanic and littoral deposits and the deposits of coal in the up- 
per part and near the westernmost exposures of the Carboniferous. At the close 
of the Paleozoic era the land area must have advanced much further westward, 
since the deposits of salt and gypsum in the upper portion of the Permian indi- 
cate the absence of open seas. During the whole of the Cretaceous period deep 
sea conditions prevailed over most of the state, since the deposits are now present 
in the western two-thirds of it after a considerable erosion. At its close the rais- 
ing of the mountains to the west caused the final retreat of the sea, the only re- 
maining deposits, the Tertiary and limited Quaternary areas, being of fresh-water 
origin. 
ORIGIN OF PRESENT DRAINAGE. 
Until the close of the Cretaceous the drainage of Kansas, or such portions of 
it as were land areas, was to the west into the Cretaceous sea, sinve the deposits 
indicate a Jand mass to the eastward. The raising of the mountains to the west 
produced a drainage slope to the east over the newly exposed Cretaceous forma- 
tions, which subjected them to a considerable erosion before the Tertiary of 
Kansas was laid down. Just what oscillations have occurred since then are not 
so easily determined. If, however, the Tertiary deposits were lacustrine to any 
extent, it would seem probable that there existed during that period a broad 
basin extending over the western part of the state far to the north and south, 
into which the drainage from the west flowed. If the sediments which produccd 
the Tertiary were simply spread out on a flood plain, similar conditions probably 
existed. It appears therefore that not until near the close of the Tertiary times 
were the Park mountains sufficiently elevated to induce a drainage from that 
region across the Arkansas plateau to the Mississippi. We may accordingly look 
upon the present physiography of Kansas as being of the latest period. 
