"Speckled" bluestones from Wales were transported and used at Stonehenge to mark major lunar cycles (Metonic and Saros cylces) because of the similarity of the speckles to the appearance of the stars in the sky at night.
The only thing erratic about the stones at Stonehenge are people posting nonsense about glacial erratics. We wrote about that old absurdity some years ago: it is an old theory, and it was as wrong then as it is now.
In our own age of alleged global warming and many clearly receding glaciers, strange as it may seem to the erratics, no "glacial erratics" even remotely close in form to those at Stonehenge have ever modernly appeared anywhere as glaciers recede.
We do not deny the existence of glacial erratics, but they do not look like the stones at Stonehenge. Besides, even if glaciers were depositing stones like this, we would expect Salisbury Plain literally to be covered with them. But it is not.
The notion that "megaliths" are glacial erratics, rather than the purposefuly erected landmark stones that many actually are, is an old erratic fantasy of erring so-called geologists and morphogeologists for whom any stone found where it should not be geologically by theory must therefore necessarily be a "glacial erratic". Once again, the science of "tunnel vision" raises its head.
The idea that stone age man could purposefully move very large stones seems not to enter the minds of the erratics so that they should take a day off from work and walk around Avebury. There it is impossible to argue that those stones are "glacial erratics" in situ. By comparison, moving the much smaller bluestones from Wales would have been a piece of cake.
Lastly, it is clear that the ancients used the force of heat, cold and water at so-called "quarries" to break stones as needed. Those modernly complaining that they do not find the "tools" they expect at these quarries indicate that they have little understanding of their subject and should be doing something else.
Check out our previous postings about the Preseli Hills, Stonehenge and immediately relatied topics at:
- King Arthur at Carn Bica Outcrop - Visual Interpretation for Those Who May Be Good at Texts but Not At Picture Visualization