3 - Aberdaron to Porth Oer
Pen y Cil - Dolerite Sill
Just up the cliff from the last photo - the reason to try to reach this section of cliff.
A Dolerite Sill , a tabular body of intrusive Igneous rock ,
intruded parallel to the layering of the sedimentary rocks of Ordovician age.
Sill is a Geological term for an Igneous intrusion between layers of older rocks.
These rocks are associated with the Mynydd Penarfynydd Igneous complex.
Ref: NW 665
Date: 08/04/2022
Location: SH 1564 2406
