End of intrusion of small dike of pegmatite at Crown Mica mine. Custer County, South Dakota. 1923.
Dates
Date Taken
1923
Summary
End of intrusion of small dike of pegmatite at Crown Mica mine, near Custer. Custer County, South Dakota. Before 1923. Plate 27-B in U.S. Geological Survey. Bulletin 740. 1923.
Summary
End of intrusion of small dike of pegmatite at Crown Mica mine, near Custer. Custer County, South Dakota. Before 1923. Plate 27-B in U.S. Geological Survey. Bulletin 740. 1923.
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