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 . DAWSON ON SPECIMEN OF DIPLOX LON greatest diameter and consists of central pith cylinder and two con centric coats of scalariform tissue fig The pith cylinder is replaced by sandstone and is about one centimetre in diameter The inner Fig Longitudinal and Transverse