1. Cambrian(?), Middle Proterozoic, and Archean rocks penetrated in a borehole near Argenta, Beaverhead County, Montana, and some paleogeographic and structural implications Author/Creator: Pearson, Robert Carl, 1926- Publication/Creation: Washington, D.C. : U.S. G.P.O., 1996 Resource Type: Book Access & Availability: Loading