1. Now that the dig has been extended for 70m or more, right to the inner end of the rocky spur, we can see that the dig site is on the floor of a small meltwater channel, similar to many of the features we can see on the flanks of the Gwaun-Jordanston meltwater channel system. It's difficult to assess how many times this channel might have been used, but its use by meltwater (probably subglacial, under very high pressure) might go some way towards explaining the long, smooth, regular wall which others tend to refer to as "the quarry face." It's probable that the channel was used both in the Anglian and Devensian Glaciations.
2. If you look carefully at the photo above you can see that the big "orthostat" resting just to the right of centre in the photo has fallen from the highest pinnacle on the ridge. I see no problem at all with a slab of this size crashing down the rock face, either in the Late Glacial or at some stage during the Holocene, and ending up exactly where it is today, some distance from the rock face. It might have slid, might have tumbled down end over end, or might have rolled. No human agency required in the process.
3. In his Moylgrove lecture, MPP placed great emphasis on the "killer fact" that a big transverse stone just downslope of the "proto-orthostat" has striations or erosional grooves on it, proving beyond doubt that other large stones have been hauled across it during earlier stone removal operations. It's lucky that I managed to have a look at it today, or this myth might have been perpetrated until the end of time -- and there would have been no way of checking, since the spoil is about to be thrown back into the dig location at any moment now.............. Anyway, they are not striations, scratches or erosional grooves. They are outcropping foliations on the rock surface, no different from those on scores of other stones to be found throughout the dig site. They follow the strike of these micro-structures. If you look at the side of the rock you can see how the foliations or "pseudo-layers" run within the rock, downwards towards the bottom left of the photo. I am 100% confident that any geologist or geomorphologist who looks at this rock would agree with me on this. Here are some pictures:
4. In the Moylgrove lecture, MPP also dismissed the idea that the excavation had reached a layer of till. He said that if there was till present, it must be much deeper down. I have news for him. In the lower part of the dig at the moment we can see some of the best till I have seen in a long time. In fact, they hit it last year, as I mentioned on this blog. (Why don't these people listen when they are given solid information?) It is probably Devensian, around 20,000 years old. Its upper surface -- as always in Pembrokeshire -- is a foxy red colour. When I saw that I was pretty convinced that I would see a rather sticky clay-rich or silty till underneath the reddish layer, and indeed, there it is for all to see:
Another erratic boulder resting on the surface of the till. This also appears to be a dolerite.