Mesas and Buttes
This is Mill Bluff, one of many isolated and rocky castle-like hills which rise abruptly from the surrounding plain. This formation is properly called a mesa (Spanish for "table") if large and butte if small.
Mesas and buttes in this driftless area escaped glacial activity and have a capping on top hard enough to resist weathering. Erosion by wind and water eventually wears away the soft sides until the weight of the overhanging cap causes it to fall.
The mounds decrease in size until the capping is all removed. Then the mound becomes a conical hill, gradually blending with the plain. Mill Bluff received its name from a sawmill operated here in the early days of settlement.
Marker can be reached from Funnel Road north of U.S. 12, on the right when traveling north.
Courtesy hmdb.org
