PETROLEUM AT CONTROLLER BAY. 97 
8. Redwood Creek. Drilled to a depth of several hundred feet in 1904. Oil now 
stands about 20 feet below the top of the casing. Quantity not known . 
9. Near head of Katalla Slough. Drilled to an unknown depth in 1904. No oil, so 
far as known. 
10. Near head of Katalla Slough. Drilled in 1902 to a depth of 36(3 feet, where a flow 
of oil was obtained. Drilled to 550 feet in 1903 without further results. In 1904 this 
Well was pumped for fuel at the other wells of the same company. II is now capped, 
the oil oozing around the casing. 
11. Near head of Katalla Slough. Drilled in 1901 and abandoned because of loss of 
tools. 
12. Near head of Katalla Slough. Drilled in 1903 to an unknown depth. 
13. Near head of Katalla Slough. Drilled in 1904 to an unknown depth. Now 
capped, the oil squirting at times in strong jets from the casing. 
14. Between head of Katalla Slough and Cave Point. Drilled in 1903 to 1,710 feet 
and abandoned because limit of outfit was reached. 
15. Katalla River. Casing sunk to a depth of 280 feet in 1903 without reaching bed 
rock. 
16. Near Katalla. Two holes have boon drilled in 1904 to 1906 on this site, a depth 
of about 1,500 feet having been reached. Work is still in progress. 
PRINCIPLES GOVERNING THE OCCURRENCE OF 
PETROLEUM. 
The four great problems of the geologic occurrence of petroleum are 
the origin of oil, the movements of oil in the rocks, the stratigraphic 
and structural distribution of the existing accumulations of oil, and the 
determination of the location and area of valuable accumulations from 
the known facts of surface geology. 
These problems are stated above in the order of increasing impor- 
tance from the point of view of immediate utility. The last problem 
can be solved in either of two ways — by expensive practical testing with 
\ the drill or by the solution of the first and second problems, together 
with a complete and accurate knowledge of the areal geology of the 
region in which the occurrence of oil is suspected. In the present con- 
dition of our knowledge the practical method is the only certain solu- 
tion of this problem. But all knowledge gained in this way, as well as 
all facts concerning the geology of the oil-bearing rocks, leads us nearer 
to the solution of the other problems, and hence hastens the time when 
we can determine within reasonable limits the presence of oil from our 
knowledge of the manner in which oil originates and accumulates. 
The first and second problems are consequently the problems of 
greatest ultimate importance and should, in a public geologic investi- 
gation, be given at least equal weight with the other or immediate 
commercial problems. 
Petroleum occurs in rocks of practically all ages from the oldest 
Paleozoic to the Recent. All known productive bodies of oil are in 
rocks of sedimentary origin, such as sandstones or sands, shales or 
clays, limestones, and conglomerates. Minute quantities of oil have, 
however, been seen in volcanic or other crystalline rocks. 
Bull. 3 14— 07 7 
