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 . MAER ON THE PREDEYONIAN green shales In addition this band and the last Dd are described as containing the Colonies III Silurian Bocks The Silurian epoch includes Barrande's etages EH Unlike the Cambrians the prevailing rocks of this series are limestones although