HawortH.| Detailed Geology of Oil and Gas. 163 
ing a plain or shelf dipping gently to the west and occupying 
a position intermediate between others above and below. The 
surface is modified by erosion, with hills here, valleys there, 
streams, channels, mounds and other irregularities interfering, 
so that any given formation, particularly a limestone forma- 
tion, is liable to have outliers some distance beyond the eastern 
edge. This is illustrated on the Montgomery county map dy 
the Stanton limestone, with an outlier covering Table Mound, 
northwest of Independence, and Walker Mound, southwest of 
Independence. Likewise, a given formation has projections 
extending westward along a stream valley where the stream 
has cut through the overlying formations, exposing the under- 
lying one farther to the west than is the ordinary, as is well 
illustrated by the Stanton limestone extending westward up a 
tributary of Elk river to beyond opposite Elk Falls, and par- 
ticularly the same limestone extending westward from Allen 
county across into Woodson county. 
These maps have represented on them the oil-wells, e@as- 
wells and dry holes, corrected up to about September, 1997. 
Possibly a few welis were omitted, but it was our endeavor to. 
make them as nearly complete as possible. 
The most productive individual horizon in the entire Mid- 
continental field is that occupied by the Cherokee shales. Prac- 
tically all the oil and gas from Caney to the east, south and 
north occur in these shales, although in a few places either oi] 
or gas has been found in overlying formations. The greatest 
production in Chautaugua county also comes from the same 
horizon, yet many of the gas-wells and some of the later oil- 
wells are supplied higher up. Westward, in the vicinity of 
Longton, Moline and Grenola, and in the gas-fields of Arkansas 
City, Augusta and Elmdale, the gas occurs probably from 
1000 to 1500 feet above the top of the Cherokee shales, al- 
though it is not known definitely just how far beneath the 
surface the Cherokee shales are in that territory. It is evi- 
dent, therefore, that while the Cherokee shales are the prin- 
cipal producers of oil and gas in this territory, yet almost any 
and every shale-bed overlying them within the entire Carbon- 
iferous area of the state may contain productive sandstones. 
Not only this, but occasionally the shales and limestones 
are small producers. It is a common matter to hear drillers 
speaking of shale gas, meaning a small but variable amount 
of gas obtained within shales themselves. Likewise, in rare 
