Author: Irving, Roland Duer
Title: On the Classification of the Early Cambrian Pre-Cambrian Formation. A Brief Discussion of Principles, Illustrate by Examples Drawn Mainly from the Lake Superior Region
Description: Washington, Gov't Print. Office, 1888. Pp. 365-455p. b/w illus. colored maps,, bound in modern stiff paper, quarto format. (Etract from the 7th Annuel Report of the Director of the U.S. Geological Survey, 1885-86). .

Keywords: Cambridan Geology Lake Superior Region Americana