Information of hydrogeologic and geologic importance from the book, "Lithofacies Maps: An Atlas of the United States and Southern Canada" (Sloss and others, 1960) detailing geologic periods, including the Cambrian, Ordovician, Silurian, and Devonian were digitized from scanned maps. Isopach contours were captured and, along with Geologic Map of North America (GMNA) information (Garrity and Soller, 2009), were used to interpolate thickness rasters for each period. Additionally, the lithofacies information on each map was also digitized. Data available in this data release include 4 compressed (.zip) geodatabases (.gdb) of geologic period feature classes, including isopach contours, lithofacies, raster interpolation masks, control points, and thickness rasters. A layer file for symbolizing the lithofacies feature classes and the metadata document are also included. Citations: Sloss, L.L., Dapples, E.C., and Krumbein, W.C., 1960, Lithofacies Maps: An Atlas of the United States and Southern Canada, John Wiley & Sons, Inc., 108 pages. Garrity, C.P., and Soller, D.R., 2009, Database of the Geologic Map of North America; adapted from the map by J.C. Reed, Jr. and others (2005): U.S. Geological Survey Data Series 424, http://pubs.usgs.gov/ds/424/.