Plumstone Rock

Somehow or other, Plumstone rock has escaped our attention.  It is a prominent rhyolite tor located on the ridge of Ordovician volcanic  rocks that runs between Roch Castle in the west (near Newgale)  and Trefgarn Gorge in the east.  The most prominent crags on the ridge are Poll Carn (Lion Rock) and nearby Maiden Castke (called by the locals the "family of lions" for obvious reasons).   

The rocks are for the most part flinty bluish rholotes, with considerable internal variation, including welded tuffs and agglomerates.  In certain light conditions the rocks appear to be pinkish or orange in colour.  The age of these rocks was disputed for many years, having been originally labelled as Precambrian -- but they now seem to be accepted as Ordovician.

The rock is hugely impressive and intimidating -- but  it is easily accessible from the Haverfordwest - Hayscastle road, and there is an easy short walk to the tor from the car parking area on the common.

It does not have the fragility of  Maiden Castle, and while the bulk of the tor is solid bedrock, on its flanks there are numerous massive detached blocks.  It is -- naturally enough -- a facvourite place for "bouldering".  I have not seen any striated surfaces on the tor, but there are some forms that are suggestive of ice moulding.  The big question is this -- what do the four tors on this ridge tell us about the history of glaciation across Pembrokeshire?