Washington, DC: United States Geological Survey/USGS/Government Printing Office/GPO, 1972. Soft cover. Item #47135
Remanent magnetization directions for lower and middle Keweenawan rocks fall into three groups that have their polarities alternately normal, reversed, and normal. 42 pages with map, columnar section, tables, figures and references. Bound in original gray stiff paper covers printed in black. Library stamp on the front cover. No other library markings, pockets or plates were ever present. A near fine copy.