What is recorded here

Porth Gron on Ynys Môn (Isle of Anglesey) features sandstone and mudstone rocks of Ordovician age, formed around 470–450 million years ago through the deposition of sediments in a shallow marine environment. The area is notable as part of the Llanberis Slate Formation, a key geological unit in the North Wales Ophiolite Belt, which provides insights into ancient oceanic crust and mantle processes.

This does not grant access. Check current paths, opening conditions and ownership before entering.