PREFACE. 
HE great development in the production of petroleum and 
natural gas in Kansas and Oklahoma, generally called the 
Midcontinental field, within the last few years, has made 
it highly desirable that a carefully prepared report on the sub- 
ject be published, giving as great detail as possible to all 
phases of our knowledge bearing upon the occurrence, origin, 
nature, uses and commerce of these two commodities. This 
Survey has been collecting data on the subject for more than 
ten years, and has published, in a fragmentary way, bits of in- 
formation from time to time in various annual reports on the 
mineral resources of Kansas. Likewise, the United States 
Geological Survey has issued a few small publications cover- 
ing certain phases of the subject. But previously no attempt 
has been made to treat the entire subject in a comprehensive 
manner. 
In the following pages the order of treatment was arranged 
from the standpoint of geology, giving first the geography and 
stratigraphy of the productive formations, next the general 
and detailed geological conditions under which they occur; 
and this is followed by an exposition of the chemical and phys- 
ical properties of oil and gas, their values for various pur- 
poses, particularly as heat producers; and lastly, the commer- 
cial aspect of the subject, which includes production, market 
value, probable future development, etc. 
As the oil and gas of Kansas occur entirely in the Coal 
Measures a discussion of their geological relations of course 
is a discussion of the Coal Measures. Much has been said and 
written about the stratigraphy of Kansas Coal Measures, in 
fact, too much. 
Years ago this Survey began a systematic study of the de- 
tailed stratigraphy of eastern Kansas. Largely because the 
existence of the Survey depended upon biennial appropria- 
tions, preliminary reports were made. Naturally, such reports 
were somewhat defective. Geologists in neighboring states— 
Missouri, Iowa, and Nebraska—have taken up the matter in 
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