Near Stillwater in Washington County, Minnesota — The American Midwest (Upper Plains)
Geology of Minnesota
The site of this tablet marks the northern limit of Lake St. Croix, impounded by the natural dam of sand and gravel, made by the Mississippi where it is joined by the St. Croix River, twenty miles below Stillwater. The valley, with its steep banks, is typical of youthful topography - of a young stream - and its size, compared with the river, indicates that a much larger volume of water flowed here when the St. Croix was an outlet of glacial Lake Duluth, the ancestor of Lake Superior. The highway and picnic grounds occupy a river terrace on which the river flowed at an earlier stage. The rock walls of the valley are chiefly sandstones formed in the sea when it covered Minnesota during the Cambrian period 500 million years ago. Because of the thickness of the beds and the excellence of the exposures along the river, these formations, wherever they appear in North America, are known as the St. Croixian series.
in cooperation with the Department of Highways
State of Minnesota
Erected 1950 by the Geological Society of Minnesota.
Location. 45° 4.882′ N, 92° 47.459′ W. Marker is near Stillwater, Minnesota Touch for map. Marker is at a scenic overlook. Marker is in this post office area: Stillwater MN 55082, United States of America.
Other nearby markers. At least 8 other markers are within 2 miles of this marker, measured as the crow flies. Tamarack House (approx. one mile away); The Warden's House (approx. 1.6 miles away); St. Croix Lumber Mills / Stillwater Manufacturing Company (approx. 1.7 miles away); 1965 Easter Sunday Floodwater Crest (approx. 1.8 miles away); 114 North Main Street (approx. 1.8 miles away); 1884 Upper St. Croix River Log Jam (approx. 1.9 miles away); Birthplace of Minnesota (approx. 1.9 miles away); 226 East Myrtle Street (approx. 1.9 miles away). Touch for a list and map of all markers in Stillwater.
Also see . . . Geology of Minnesota. Wikipedia entry. (Submitted on July 1, 2011.)
Categories. • Waterways & Vessels •
Credits. This page was last revised on June 16, 2016. This page originally submitted on July 1, 2011, by Keith L of Wisconsin Rapids, Wisconsin. This page has been viewed 571 times since then. Photos: 1, 2, 3, 4, 5, 6. submitted on July 1, 2011, by Keith L of Wisconsin Rapids, Wisconsin.