Illinois Preliminary Geologic Maps (IPGM)
Many Illinois Preliminary Geologic Maps (IPGM) were originally 1:24,000-scale STATEMAP products, but the series also includes maps of other scales and funding sources. In addition to bedrock and surficial geology, this series may include geologic themes such as drift thickness, bedrock topography, and others. Some IPGMs will be upgraded to the Illinois Geologic Quadrangle (IGQ) series. IPGM maps receive a brief internal scientific review and may not conform to ISGS cartographic standards. They are available for sale as paper copies and as free downloadable PDF files through the ISGS Web site. Digital (GIS) data are available for some of these geologic maps. The IPGM series is no longer used for new publications.
Other ISGS map Series
Updated 06/19/2012 SLD