Top Ten Pembrokeshire erratics

1. Picrite boulder at Porthlysgi, near St Davids.  A very famous erratic made of "picrite" which appears very different from anything known in Wales -- therefore it is suggested that it might have come from Scotland.    It fell over the cliff and was lost for many years, but then it was hauled back up the cliff again in a heroic erratic rescue.  In May 2023 I found it again and recorded its precise position on the clifftop.

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2.  The Flimston boulders.  There are seven of them in the old churchyard, gathered up from the surrounding area and intended to be used as grave headstones.  Four of them stand in a row and have memorial tablets affixed -- the other three are lying unused in the long grass.  Origins are unknown, but the best bet at the moment is that the boulders have come from the St Davids Peninsula.

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3.  The Sleek Stone "super erratics" near Broad Haven.  There are several of them, the largest of which weighs c 75 tonnes.  It is a quartz porphyry, according to Cantrill -- possibly from Ramsey Island.  It rests on a broken platform of Coal Measures sandstones and shales.

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4.  The Ramsey Sound super erratic, made of grey or purple tuff.  Origin: possibly Ramsey Island.  It has probably not travelled far -- there are outcrops of the same rock type in the vicinity.

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5.  Druidston super-erratic.  An enormous erratic located in the valley upstream from the beach.  Difficult to get at, but it appears to be a dolerite, probably from the St David's Peninsula.  In the stream cutting there are multiple other large igneous erratics, associated with the thick Irish Sea till exposure at the head of the bay.

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6.  St Bride's Haven erratic pair.  These dolerite erratics are on the beach at the head of the bay -- you walk past them if you are walking on the coast path.  They rest on ORS bedrock -- the colour difference makes the erratics stand out prominently.

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7.  Llan spotted dolerite erratics, Lampeter Velfrey.  Spotted dolerite erratics incorporated into a ruined burial chamber on the lowlands of South Pembrokeshire (mostly underlain by sedimentary rocks).

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8.  Glan yr Afon erratic cluster, near Crosswell.  I'm mystified by these, because they are nearly all spotted dolerites -- but found to the NORTH of Mynydd Preseli within sight of the nearest known spotted dolerite tor called Carn Goedog.  But iceflow here was (or so we think) from the north towards the south. Were the boulders carried north by the ice of a small local ice cap?  Did they come from a spotted dolerite outcrop that we know nothing about?  Or are they not in a natural position at all -- were they collected up by people in historic time, looking for attractive building stones?

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9.  The Loving Stone, Loveston Farm, near Kilgetty.  This massive igneous erratic is clearly not in its original position.  It must have been found nearby, but it has been moved around in the farmyard, having been treated as a nuisance.  It has probably come from the St Davids Peninsula.

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10.  The Russia Stone, near Cwm Gwaun.  This massive monolith is one of a cluster of stones known as the Russia Stones. Some of the stones might have been used in Neolithic stone settings, but the farmer told me that this one was recumbent and was moved a short distance so that it could be used as a gatepost.  This stone has probably not travelled far -- there are a number of dolerite outcrops in the vicinity.

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Note:  I have resisted the temptation to include perched blocks in this list.  There are plenty of them -- but although they may have been dislodged from their original positions by overriding ice, most of them have only travelled a few metres, so they are not quite erratic enough to make the list.