4 - Trearddur to Holyhead
Rock folds - 2
From the Bridge to South Stack Lighthouse a view of the folds and fault in the metasedimentary Cambrian - Ordovician Period rock strata (about 500 MYO)
The rocks in the channel below which separates Yny Lawd (South Stack) from Ynys Gybi (Holy Island)
are part of a dyke intruded into the South Stack Group rocks.
Ref: NW 1161
Date: 30/06/2022
Location: SH 2040 8228
