Sun River Canyon: mouth of the canyon from foothills several miles east. Lewis and Clark County, Montana. 1920.
Dates
Date Taken
1920
Summary
Sun River Canyon: mouth of the canyon from foothills several miles east, showing the notch cut nearly 1,000 feet deep through the lower limestone wall, probably in interglacial time. Lewis and Clark County, Montana. September 21, 1920. Plate 43-A, U.S. Geological Survey Professional paper 174. 1932.
Summary
Sun River Canyon: mouth of the canyon from foothills several miles east, showing the notch cut nearly 1,000 feet deep through the lower limestone wall, probably in interglacial time. Lewis and Clark County, Montana. September 21, 1920. Plate 43-A, U.S. Geological Survey Professional paper 174. 1932.
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