Resource provided by UW-Madison Robinson Map Library. This layer consists of a 1:250,000-scale polygon coverage containing depth-to-bedrock estimates and related information used in preparing the GCSM for Wisconsin. The primary source for this data layer is a 1973 map at 1:1,000,000 scale published by the WGNHS and USGS. Where more recent information was available, the USGS updated the 50-foot and 100-foot contours of the depth-to-bedrock map at a scale of 1:250,000. Soil associations data, and other information, were used to add a 5-foot contour to the data layer.