The Geological and Natural History Survey of Minnesota. The twentieth annual report for the year 1891.

Winchell, N.H.2010-01-072010-01-071893https://hdl.handle.net/11299/56264Summary of the geological and natural history studies carried out in Minnesota during 1891.engeologynatural historyMinnesotalandformsThe Geological and Natural History Survey of Minnesota. The twentieth annual report for the year 1891.Map