Following on from yet another statement (in the latest edition of "Current Archaeology") that the builders of Neolithic stone monuments such as Stonehenge (and the putative "proto-Stonehenge" which will no doubt be traced to Bedd Arthur) actually had a preference for elongated pillars of dolerite, it's worth pointing out that this is nonsense. In the "Current Archaeology" article, Mike Parker Pearson suggests that his imaginary bluestone quarrymen were targetting "tall, thin, natural pillars" at Carn Goedog in particular, which were "perfect raw material for standing stones". He even suggests that a tall pillar of foliated rhyolite was extracted from a wondrous recess near the tip of the Rhosyfelin "quarry" as well.
However, out of 43 known bluestones at Stonehenge, there are only six elongated pillars -- all in the remnants of the bluestone horseshoe. They are numbered 150, 61, 62, 63, 69 and 70. There are a couple of other bluestones in the bluestone circle that might optimistically be referred to as "stumpy pillars" -- but the rest are simply boulders or slabs of various shapes and sizes.
I have done a lot on this blog already on the subject of bluestone shapes. Just type in "bluestone shapes" or "bluestone erratics" to pick up on some of the posts. See also this:
and the "Stones of Stonehenge" website:
On the latter site you can see many illustrations of the stones, from all sorts of different angles. It is often assumed that the bluestone stumps found in both the bluestone circle and bluestone horseshoe settings were elongated pillars; but there is no logic in this thinking, and they are more likely to have been slabs or boulders like most of the remaining standing and fallen stones.
Clearly there was a degree of selection of "elongated" bluestones for the final stone setting at Stonehenge -- but that is best interpreted as a "design" decision made by the builders at the time, based on an assessment of the resources that they had available. And those resources -- as we have said many times before -- were really rather limited: namely a mottley collection of glacial erratics of all shapes and sizes, collected up from somewhere in the Salisbury Plain landscape. They gathered up as many stones as they could find, and then gave up on the enterprise, and had to make the best use of what they had,
The idea that the Neolithic builders of Stonehenge actually went to West Wales with a view to finding splendid elongated pillars -- or that they or some subordinate or superior tribe brought in such pillars from a preexisting stone monument in Wales -- is pure fantasy, and is best forgotten about.