1. Bedrock geologic map of the Grafton quadrangle, Worcester County, Massachusetts Author/Creator: Walsh, Gregory J. Publication/Creation: [Reston, Va.] : U.S. Geological Survey ; Denver, Colo. : For sale by U.S. Geological Survey, Information Services, 2011 Resource Type: Map Access & Availability: Loading
2. Geologic map of the Bailey 30ʹ by 60ʹ quadrangle, north-central Colorado Author/Creator: Ruleman, C. A. (Chester Allan), cartographer, writer of added text Publication/Creation: Denver, Colo. : For sale by U.S. Geological Survey, Information Services Resource Type: Map Access & Availability: Loading