Preface. 3 
to express my personal appreciation of this great work per- 
formed by him, largely as a matter of love, and to give it as 
my belief that no piece of work has ever been done by an 
American geologist more thoroughly or more conscientiously 
than the work done by Mr. Bennett. 
Professors H. B. Cady and D. F. McFarland, of the Chem- 
ical Department, University of Kansas, consented to make a 
series of analyses of Kansas gases, samples of which were 
furnished them at the expense of the Survey. The investiga- 
tion proved to be more interesting than anticipated, which re- 
sulted in gas samples being gathered practically all the way 
from the Atlantic to the Pacific oceans; not as many, however, 
as all of us wished we had time and opportunity to gather. 
They have written an elaborate report on their work, in which 
is included a good summary of gas analyses by others, making 
their chapter one of unusual interest. 
In a similar manner Prof. F. W. Bushong, of the Chemical 
Department, University of Kansas, made an extended series of 
analyses of oil and wrote a chapter on the same, corresponding 
in interest to the one just mentioned for natural gas. 
In the discussion of location of oil and gas, particularly the 
latter, it was deemed desirable to give in great detail the nat- 
ural conditions of occurrence rather than a lengthy discussion 
of theories as to their origin. The latter question, however, 
had to be touched upon. It is probable that no one phase of 
our studies of oil and gas would become of more practical 
value than the study of their origin, provided we could only 
reach correct conclusions. But the great difficulty is in knowing 
that one is correct. If one could positively determine when 
and where and how these hydrocarbons originated, quite likely 
one would have a very great advantage in determining their 
present locations. As a matter of interest, and also of direct 
value in stratigraphic correlations, a considerable amount of 
paleontology has been included in the report, which the 
thoughtful reader will recognize as having great practical 
value. 
ERASMUS HAWORTH, 
State Geologist. 
