HawortH.| Detailed Geology of Ow and Gas. 171 
section be made in a similar manner along the ocean beaches 
in general, it will be found the character of the sand changes 
more frequently in a given distance. In other words, it is 
possible to find long stretches of sandy beach with practically 
uniform characters parallel to the coastal line, although the 
mere fact of parallelism does not guarantee uniformity of 
conditions, while in transverse directions almost invariably 
we find quite a variation of conditions. 
The lesson is easily learned. A long stretch of uniform 
conditions, such as along the line between the Osage and 
Cherokee nations, or along the Neosho river valley from Cha- 
nute to Humboldt, or many other places that might be named 
in almost any oil-field in America, doubtless corresponds to a 
modern ocean beach as described; while areas filled with rapid 
variations, dry wells and good wells mixed together apparently 
indiscriminately, doubtless correspond to the other character 
of coastal beaches. In the matter of direction, also, the sim- 
ilarity is great. Our Atlantic coast in general trends north- 
east and southwest, but how easy it is to find local trends in 
many other directions. Likewise, the Appalachian oil-fields 
and Midcontinental oil-fields in general trend northeast and 
southwest, but in each of them locally we have many variations 
from such. 
Relation of Geologie Structure to Oil and Gas Pools. 
ANTICLINAL ARCHES AND SYNCLINAL TROUGHS. 
In many oil-fields and gas-fields there seems to be a certain 
definite relation between local geologic structure and the pools 
in which oil and gas are found. This idea was first worked out 
for the Appalachian region. Briefly stated, it is that gas-pools 
and oil-pools are found under anticlinal arches and along the 
branches or limbs of such arches, while water-pools should be 
expected under the synclinal troughs. Nature in her modifica- 
tions of the horizontal bedding-plains of stratified rocks often 
has thrown them into undulating positions of crests and 
troughs. Through the influence of certain dynamic processes, 
rock strata have been lifted here and depressed there, pro- 
ducing an arch-like dome in one place and a corresponding 
trough in another. If, now, a productive sandstone should hap- 
pen to occur in such a place far beneath the surface with an 
overlying oil-tight and gas-tight shale-bed, the tendency would 
be for the three materials—water, oil and gas—to arrange 
