56 KANSAS ACADEMY OF SCIENCE. 
DRAINAGE OF THE PRAIRIE PLAINS. 
The drainage of the prairie plains is due primarily to the eastward slope of the 
surface. By reference to the map, it will be seen that, with the exception of the 
Kansas river, all the streams rise within the area. A secondary feature is the dip 
and strike of the rocks. In general, the dip is to the west and the streams flow 
at right angles to the strike, but slight deformations of the strata have caused a ~ 
deflection of some of the streams tothe south. There isan anticlinal ridge which 
has determined the divide between the Neosho and Osage river systems. In Mis- 
souri this divide continues into the Ozark region, to which the anticlinal is, no 
doubt, structurally related. Near the eastern border of the state this divide is 
spoken of by the residents as the Ozark ridge, and they will tell you that it can 
be traced to the Ozark mountains: but many of them mistake the escarpments 
which cross the ridge for the ridge itself. Along the southern border of the state 
the dip is to the southwest, and the streams here become more directly tributary 
to the Arkansas, which finds its way through the Ozark region in a synclinal 
trough.* 
Spring river, which crosses the southeast corner of the state, flows along the 
line of contact between the Subcarboniferous and Carboniferous formations, and 
has literally slid down the extreme border of the Ozark dome, eroding the shales 
of the Carboniferous and accommodating itself to the uneven surface of the Sub- 
carboniferous. In the territory the Neosho, to which Spring river is tributary, 
occupies a similar position, and is deflected to the west considerably before it 
reaches the Arkansas. 
RESULTANT TOPOGRAPHY. 
The formations over which the streams flow are beds of limestone alternating 
with beds of sandstone and shale. The unequal yielding of these materials to 
erosive agencies has produced in general a terraced surface, the limestones pro- 
tecting the escarpments while the shales and sandstones below have been carried 
away by the streams. t 
The inclination of the strata has produced a gradual slope (back slope) from 
the top of one escarpment to the base of the next higher. Not infrequently a 
stream cuts off a portion of an escarpment, producing a mound or ridge, and the 
ridge in turn is broken up into a row of mounds. In case the more resistant 
strata are anywhere discontinued or lose their importance the escarpment fades 
out, and the softer beds add their thickness to the escarpment geologically next 
higher. Likewise if the softer strata give place to more resistant ones, é. g., a 
limestone system appears in a position where in other cases there is a shale bed, 
a new escarpment is developed. If a shale bed gradually thins out the adjacent 
limestones are merged into the same escarpment; and, on the contrary, if two 
closely associated systems are separated at any place by the thickening of inter- 
vening shales, their lines of outcrop diverge and two escarpments are produced. 
A stream fiowing upon a back slope will gradually slide down upon the in- 
clined strata until it reaches the base of the next escarpment, cuts through the 
underlying formation, or reaches base level. In the latter case it would widen 
its valley, producing a plane independent of the dips of the strata. Along a 
single stream this area would be called a bottom land. When produced over large 
area by a stream and its tributaries, or by several streams, it is called lowland. 
The prairie plains region in Kansas is coextensive with the Carboniferous for- 
mation. A section { made from Galena to Grenola passes across the entire for- 
* Geo. H. Ashley, Geology of Paleozoic Region of Arkansas: Proc. Am, Phil. Soc., May, 1897. 
+ Vide Haworth: University Geol. Surv. of Kansas, vol. I, ch. 10. 
tThis section, made by the writer, was published in the Univ. Geol. Surv. of Kansas, vol. I; 
also in vol. IIT, q. v. 
