1. Digital bedrock geologic map of the Ashland and the northern part of the Ironwood 30ʹ x 60ʹ quadrangles, Wisconsin and Michigan Author/Creator: Cannon, William F. Publication/Creation: [Denver, Colo.] : [For sale by USGS Information Services (Open-File Report Sales)]. Resource Type: Map Access & Availability: Loading
2. Distribution of late Quaternary wind-deposited sand in eastern Colorado Author/Creator: Geological Survey (U.S.) Publication/Creation: [Reston, VA] . : U.S. Dept. of the Interior, U.S. Geological Survey, 2005 Resource Type: Map Edition: Version 1.0. Access & Availability: Loading