Prominent linear features interpreted as faults were plotted from aerial photographs of southeastern Alaska, and the resultant patterns were analyzed with reference to the literature and to the field relations determined by the writers and other geologists of the U. S. Geological Survey. The faults, as interpreted, seem to belong to a well-defined and widespread system that trends northwesterly and to three ill-defined systems that trend northerly, northeasterly, and easterly respectively. The faults are part of a system of fractures subparalleling the Coast Ranges and the North Pacific coast of British Columbia and Alaska.

Movement on the faults in southeastern Alaska took place during late Mesozoic, Tertiary, and possibly Recent times. A major lineament, the Denali lineament, can be traced for about 1600 miles, from southeastern Alaska northwest along the arcuate Alaskan Range and thence southwest to Bristol Bay.

Most of the hot springs of the area are located on conspicuous faults. Some of the carbonated springs are on linears, but some are not. Sulfur springs seem to be unrelated to linears.

The writers suggest that certain mineral deposits in southeastern Alaska are spatially related to certain faults, particularly those of the northwest-trending system. Data support this thesis for the mineral deposits of the Chichagof-Sitka belt and the Juneau gold belt.

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