The Wisconsin Glaciation (the most recent cycle of climate cooling and glacier expansion in North America) had its most profound impact on Wisconsin when a huge sheet of ice advanced southward form Canada through the Lade Superior and Lade Michigan basins into Wisconsin. The ice sheet must have been several hundred feet thick near the margin, where the surface of the ice was quite step. Farther from the margin, it flattened out to a gentle rise of only a few feet per mile toward the northeast. As with modern glaciers, the surface of the ice was probably steeper when it was advancing than when it was receding.

The maximum extent of this ice sheet in Wisconsin is marked by a nearly continuous moraine that accumulated along the ice margin. This is what you see when you look at the mound. The margin of the ice sheet was lobate. The Superior Lobe of this ice sheet made this mound; When the ice sheet melted it dropped rocks, etc. that came from the Lake Superior Basin. I think that Willow River was formed at this time to drain the water from the melting ice.

Your Tasks

Look at the St. Croix Moraine where rock shows and email me what color it is and if its grain size is big in-between or small (sand, silt or clay) rock . This rock (if you haven't picked the bedrock) came from the direction of the Lade Superior Basin (note: there is no right are wrong answer.). Also email me the elevation here along with the GC code of this cache of this earthcache. Do not wait for a answer to log this cache. Answers must be emailed to me within a reasonable amount of time after logging this cache or you log will be deleted.

Submitted DNR form to Aaron Mason

Information came from the book "Roadside Geology of Wisconsin" by Robert H. Dott, Jr. and John W. Attig