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:
Geological Survey of Illinois BHL. Geological Survey of Illinois Table of Contents biodiversitylibrary org title Illinois Worthen Amos Henry NOTINCOPYRIGHT Biodiversity Heritage Library Check categories November PDold Geological Survey of Illinois Images uploaded by Files from the Biodiversity Heritage Library