4 - Porth Oer to Porth Towan
![Precambrian Gwna Rocks](https://amazon.clikpic.com/daevans/images/NW_155_precambrian_gwna__north_wales_coast.jpg)
Precambrian Gwna Rocks
The Gwna Group are a chaotic collection of sedimentary and igneous rocks some 610 million years old.
Since deposition the group as a whole has been subject to low grade metamorphism
producing rocks of many colours.
Ref: NW 155
Date: 29/09/2021
Location: SH 2058 3473