This feature layer, utilizing data from the U.S. Geological Survey, portrays the State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. The SGMC represents a seamless, spatial database of 48 State geologic maps. Per USGS, "A national digital geologic map database is essential in interpreting other datasets that support numerous types of national-scale studies and assessments, such as those that provide geochemistry, remote sensing, or geophysical data. The SGMC is a compilation of the individual USGS releases of the Preliminary Integrated Geologic Map Databases for the United States."

A full discussion of the procedures and methodology used to create this dataset is available in the accompanying report: Horton, J.D., San Juan, C.A., and Stoeser, D.B, 2017, The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States (ver. 1.1, August 2017): U.S. Geological Survey Data Series 1052, 46 p.