SOME TRIASSIC FOSSILS FROM SOUTHEASTERN 
ALASKA* 
WALLACE W. ATWOOD 
On the north shore of Hamilton Bay, a small re-entrant on the 
northwest coast of Kupreanof Island, there are rock exposures 
which have yielded certain Triassic fossils that may prove to be 
of special value in paleontologic studies. 
From reports prepared by F. E. and C. W. Wright, Spencer 
Brooks, Kindle, and some others, it is evident that the more wide- 
spread geologic formations of southeastern Alaska outcrop in 
roughly parallel north-south belts; that the formations consist, 
in part of igneous rocks, in part of sedimentary rocks, and in part 
of metamorphic rocks; that most of the formations have suffered 
from intense deformation; that numerous intrusions of igneous 
rocks have occurred; and that the structural relations are exceed- 
ingly complex. 
The formations included in this complex of older rocks vary 
in age from early Paleozoic to Triassic. They border and nearly 
surround the Tertiary coal basins that have thus far been located 
in this portion of Alaska. Detailed description of these formations 
as they appear at various localities may be found in the reports 
of the Alaskan Division of the United States Geological Survey, 
referred to above. 
At Hamilton Bay the older rocks include some of Paleozoic 
age and some that are of Triassic age. They include limestones, 
argillites, limestone conglomerates, shales, and _ sandstones. 
Associated with these beds there is considerable basalt of a much 
younger age. The sedimentary beds are highly inclined and are 
a portion.of a closely folded series of strata. They outcrop on 
the north shore of Hamilton Bay, and there form the northern 
limit of the area underlain by the Tertiary coal-bearing series. 
* Published by permission of the Director of the United States Geological Survey. 
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