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:
The Quarterly journal of the Geological Society of London . PROCEEDINGS OF THE GEOLOGICAL SOCIETY Mar the one to the other Even of these genera that do transgress the line the Primordial and Silurian rocks contain distinct species while the intervention of the whole of the Tremadoc rocks containing remarkable assemblage of