134 
ALASKAN MINERAL RESOURCES IN 1904. 
[bull. 259. 
whale continuing to the bottom of the hole. The well was cased to a 
depth of 630 feet. Oil and gas were encountered at a depth of 770 
feet, there being three small oil sands, each 6 to 8 inches thick and 4 
or 5 feet apart. The production of the well was estimated at 10 bar- 
rels. The caving rock was encountered at 830 feet. Work was 
stopped at a depth of 900 feet at the end of the season. Considerable 
gas was encountered at various depths, the pressure at times being 
strong enough to blow the water up in the derrick to a height of 
20 feet. a 
A well at Dry Bay was drilled to a depth of 320 feet in the summer 
of 1902 without encountering oil. The tools were then lost and the 
hole was abandoned. In August, 1903, a new well was started in close 
proximity to the first, but not much was accomplished, and work was. 
discontinued a few months later because of an accident to the machinery. 
Nothing has been done during last season. 
THE COLD BAY PETROLEUM FIELDS. 
The hurried observations which the writer made in this field in the 
summer of 1903, and which have been already published, 6 have been 
supplemented by a much more careful examination during the summer 
of 1904. Many new facts have been obtained which make it necessary 
to redescribe the geology. 
GEOLOGY. 
STRATIGRAPHY. 
The following rocks are exposed in the Cold Bay-Becharof Lake 
region : 
General section in the Cold Bay-Becharof Lake region. 
Name of formation. 
Naknek forma- 
tion. 
Enochkin for- 
mation. 
Age. 
Post- Jurassic 
Upper Jurassic 
Middle Jurassic 
Triassic 
Pre- Jurassic 
Lithologic character. 
Volcanic rock, probably 
andesite or basalt. 
Arkose, conglomerate, 
sandstone, and shale. 
Shale, sandstone, and a 
little limestone. 
Shale, limestone, and 
chert. 
Granite, syenite, etc 
Thickness in feet. 
3, 000 to 5, 000 
2,000 
The coarse crystalline rocks (granite, syenite, and rocks of similar 
texture) occur in a belt that runs parallel to the length of the Alaska 
Peninsula. They cross the lower end of Becharof and Naknek lakes 
and possibly underlie the Cold Bay region. 
a Information furnished by Mr. August Bowser. 
bBull. U. S. Geol. Survey No. 225, 1904, pp. 380-382; Bull. U. S. Geol. Survey No. 250, 1905. 
