1. Precambrian deposits of zinc-copper-lead sulfides and zinc spinel (gahnite) in Colorado : an interim report evaluating these Precambrian deposits as potential resources of base and precious metals Author/Creator: Sheridan, Douglas M., 1921- Publication/Creation: Washington : U.S. G.P.O. ; Alexandria, VA : For sale by the Distribution Branch, U.S. Geological Survey, 1984 Format: Book Is Part Of: U.S. Geological Survey bulletin, no. 1547-1553. Access & Availability: Loading
2. Precambrian deposits of zinc-copper-lead sulfides and zinc spinel (gahnite) in Colorado Author/Creator: Sheridan, Douglas M., 1921- author Publication/Creation: [Reston, Va.] : Department of the Interior, United States Geological Survey, 1984 Format: Book Access & Availability: Loading