Thanks to Dave M for this, sent with a recent letter. Some will have happy memories of this --the old Ladybird book first published in 1961. Not at all sure how many editions it went through, or how much the text and the illustrations changed over the years. Anyway, above we see a wonderful picture and some splendid stuff about 30 tonne rocks being transported from Pembrokeshire to Stonehenge. Wedges, water, hammers and wooden levers feature. Fair enough...... the quarrymen would have had access to all of these.
In his letter, Dave raises these points:
As part of the recent spat about quarrying, has anyone suggested a list of attributes that a man made quarry would have, that could be tested by observation in a scientific process? I guess though that the nature of broken rock and later natural processes would probably conceal or destroy any such evidence. The list of attributes indicating natural process would probably be much greater.
Out of interest, can any of the stones fallen on the ground at Rhos y felin be matched to spaces in the outcrop above, or are they all of such variable shape that it would be very difficult to attempt to analyse? The upper surface of the outcrop is also too heavily weathered and suffered from multiple rock falls to reconstruct with any conviction.
These are perfectly sensible things for discussion. I'm not aware of a list of attributes which might feature in a genuine man-made quarry. Does anybody know of a list in a sort of quarry-hunter's manual? I agree that evidence is incredibly hard to describe or define -- and that is why we have a group of archaeologists looking at Rhosyfelin and describing with great conviction a whole range of so-called "engineering features" that are completely invisible to a group of geomorphologists. Clearly you need the eye of faith to see them -- and that seems to some to be a good enough substitute for visible hard evidence.
I'm not sure that any of the stones on the rockfall bank at Rhosyfelin can be accurately "fitted" to existing "spaces" on the rock face. The trouble is that as they fall many of them break, and the broken bits become separated and buried beneath other debris. If I was an archaeologist I would probably argue that if there are no stones which match spaces, that means they they have been taken away by the quarrymen and used somewhere else! I made a start on some work on this, having recognised that you can see on many of the large rocks those faces which were uppermost, or outward-facing, since they are more weathered than those on the inward-facing sides or on the flanks -- but that exercise would be rather time-consuming. Maybe something like this will be done when samples are taken for cosmogenic dating in the future -- because exposure times on different rock faces are quite critical to sorting out a reliable chronology for the site.