This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Geologic Map Lake Superior MN WI MI. LargeImage en Bedrock geologic map of the US area bordering Lake Superior in Minnesota Wisconsin and Michigan Minnesota Geological Survey University of Minnesota ftp mngs umn edu jp Morey Sims Cannon Mudrey Jr Southwick PDMGS Geological maps of Wisconsin Geological maps of Minnesota Geological