Peterson Creek occupies a steep narrow avalanche-debris-filled valley with numerous small waterfalls and cascades. There is little accumulation of alluvial gravels until it approaches tidewater. Bedrock in this area is the Valdez Group of Late Cretaceous age (Nelson and others, 1985) and consists of massive greenstone and greenstone tuff, along with small amount of interbedded shale. The greenstone is typically a dense, fine-grained, green rock enclosing abundant small, angular fragments of slate (Capps, 1916).

A hand-sorted rock pile and suction dredge pit remain at the site. Placer mining has yielded less than 800 ounces of gold (Cobb and Tysdal, 1980). A concentrate sample from near the mouth of the creek contained scheelite, chalcopyrite, native copper, and gold. Significant quantities of gold reportedly occur on bedrock and in bedrock fractures, but samples collected by the U.S. Bureau of Mines contained only trace amounts of gold (Jansons and others, 1984).