1. Distribution and abundance of chromium, determined by spectrographic analysis in nonmagnetic fraction of heavy-mineral concerntrates from stream sediments, Petersburg area southeast Alaska [cartographic material] Yale Public content 1983. 2023-07-18T19:05:11Z. 2023-07-21T21:37:06Z. Geological Survey (U.S.). U.S. Dept. of the Interior, Geological Survey. English. cartographic image. Public. Alaska, Petersburg Region, and Alaska.