The Roche-A-Cri mound is an area in Wisconsin that was never glaciated even though large continental glaciers completely surrounded the area.  The region is over 14,500 square miles and as a consequence no till is found over the region.  It is still unclear why the area was never covered. At the site here, is an example of the many rock pinnacles that stand out because of the lack of glaciation.  Roche-A-Cri is a precipice of 300 foot Cambrian sandstones.