Detailed geologic maps of recently active copper mines, Houghton and Keweenaw Counties, Michigan / by H. R. Cornwall [and others]
Contributors: Cornwall, H.R.
Series: U.S. Geological Survey.  Open file report 50-4
Publisher: Dept. of the Interior
Place of publication: Washington
Language: eng
Number of pages: 43
Subjects: Geology - Michigan - Houghton County
Notes: 11