54 PETKOLEUM OF PACIFIC COAST OF ALASKA. [bull. 250. ] 
STRUCTURE. 
The rocks in the vicinity of Cold Bay are very gently folded. The 
dips are low over wide areas and the zones of steep dip are narrow 
and infrequent. 
It has been stated that there is a great anticline seaward, parallel 
to the southern coast, that has its axis near the ends of the forelands. 
This view is sustained by the fact that on at least one of these promon-l 
tories rocks older than the Jurassic are exposed, but the writer has not 
seen any evidence which would show how far seaward the southeast] 
dip may extend. This fold extends from Katmai to the cape at the 
east entrance to Cold Bay. No land extends far enough seaward 
below Cold Bay to reach the axis of this fold. The strike and the! 
direction of the axis average about N. 45 E. The northwest dip sel- 
dom exceeds 0° on the forelands. It is considerably steeper on the 
east shore of Cold Bay. 
There is a syncline parallel to this and northwest of it which exl 
tends from near the mouth of Dry Bay along the west shore of Cold' 
Bay to the high bin if s above the mouth of Teresa Creek. At this 
point it is cut off by a fault which crosses the head of the bay and 
extends up the valley* of Dry Creek. 
A long anticline is exposed in the hills southwest of the bay, the axis 
reaching the shore a short distance from Portage Bay and extending 
thence inland in a general northeast direction. The maximum dips 
observed on the southern flank of this fold were about 2° to 10°; on 
the northern, 12° to 16°. Strikes of N. 2° E. and N. 10° E., respec- 
tively, were noted. The steeper dips were apparently confined to a 
narrow zone, beyond which a dip of 8° continued for a considerable 
distance. These observations of the writer show a structure corre- 
sponding to that which has been reported from the region of Portage 
Bay, Avhere an anticline with a northeast axis is said to parallel the 
south arm of the lake in such a position that, if continued to the loca- 
tion of the oil derricks west of the shore of Cold Bay, it would coin- 
cide with the anticline seen by the writer and described above. The 
rocks exposed in the immediate vicinity of the oil derricks lie almost 
or quite horizontal. The dip in the hills south of the derricks is 
southwest at a low angle, while in the hills north of the derricks it is 
northerly at an average angle of 8°. According to report, the north- 
west dip is reversed near the center of the peninsula, so that part of 
Becharof Lake lies in a syncline, while near its northwestern shore a 
sharp anticline is said to rise, which brings to the surface not only the 
entire sedimentary series, but also a mass of crystalline rocks that 
form the core of the peninsula throughout most of its length. 
It may be seen from the descriptions given above that the most strik- 
ing structural features are an anticline with a northeast-southwest axis 
