martin. 1 GEOLOGY OF COLD BAY REGION. 53 
The coarse crystalline rocks (granite, syenite, and rocks of similar 
texture) occur in a belt parallel to the length of the Alaska Pen- 
insula. They cross the lower end of Becharof and Naknek lakes 
and possibly underlie the Cold Bay region. 
The Triassic rocks occur on Cape Kekurnoi at the eastern entrance 
to Cold Bay, and on some of the capes and islands to the northeast- 
ward. They doubtless underlie the Jurassic throughout the Cold 
Bay region. 
The Enochkin formation occupies both shores of Cold Bay, except 
at the northeastern promontory (Cape Kekurnoi) and at the head of 
the bay. It also extends in a belt along the shore of Shelikof Strait 
from Cold Bay to Dry Bay and probably as far beyond as Portage 
Bay. 
The Naknek formation forms the shore of the head of Cold Bay 
and occupies the entire interior region as far west as Becharof Lake 
and as far north as Katmai. 
The following section was measured on the east side of Rex Creek 
about 1 mile above the head of Dry Bay : 
Section on Rex Creek, Cold Bay region. 
Naknek formation : Feet. 
Arkose, sandstone, and shale 6004- 
Enoehkin formation : 
Shale and sandstone 500 
Sandstone 90 
Argillaceous shale 400 
Sandstone, shale, and conglomerate 300 
The post-Jurassic volcanic rocks occur in a discontinuous belt 
near the center of the peninsula. This belt includes several vol- 
canoes which have been active in comparatively recent time. The 
lavas are probably all either andesite or basalt. 
It may thus be seen both from the previous observations quoted 
above and from the work of the writer that the rocks exposed in 
the immediate vicinity of Cold Bay are entirely Mesozoic. They 
carry Jurassic fossils everywhere except at the promontory on the 
east side of the bay, where Triassic fossils have been found. 
Mount Peulik, the high peak on the southern shore of Becharof 
Lake, is a volcano that has probably been active in comparatively 
recent times. It is one of the many volcanic mountains which extend 
along the central axis of the Alaska Peninsula, and has apparently 
broken through the Jurassic sediments. Other similar mountains 
extend in a northeasterly direction from the north shore of Becharof 
Lake to and beyond the head of Naknek Lake. 
Glacial deposits are probably entirely lacking in this region, except 
as they are reported in the moraines of small living glaciers on the 
higher mountains. 
