I'm often asked this question: "If there really are glacial deposits on or near Salisbury Plain, and if the bluestones at Stonehenge came from an assemblage of erratics, where are all the other erratics?" Well, I have to admit that there is nothing identified thus far which could be called with confidence "a glacial deposit" or even "a glacial landform." But there are erratics scattered all over the place, as i have described in my book. The most famous is of course the Boles Barrow bluestone boulder. One day I hope that somebody will do a systematic search on Salisbury Plain and in the villages around Stonehenge. But here is one stone that needs petrographic analysis. The shaped stone in the centre of this photo is built into the side of the little prison in the centre of Shrewton, not far from Stonehenge. It's called "The Blind House". To me the block (note the bluish-grey colour) looks like a well weathered block of dolerite, similar to those in some of the Stonehenge orthostats. The stones around it are quite different -- as indeed are all the other stones used in the building. I think these others are all blocks of sarsen.
So how did this bluish stone get to Shrewton? I would argue that it was probably picked up locally and shaped for the job in hand. Others would no doubt argue that if it really is a piece of Pembrokeshire dolerite, it must have been quarried from Stonehenge, thereby helping to account for the shortage of bluestones left behind on the site today..... That's the sort of thing the archaeologists always say! Look how convoluted the arguments got in trying to "explain away" the Boles Barrow bluestone.
To get a closer look at the stone, click on the image.
5 comments:
Next time I pass through Shrewton, I will take a look!
Isobel
At Avebury many of the buildings seem to be constructed from some of the sarsen stone that are no longer in those circles--such as the manor house and the wall around it. No doubt it was resourceful to use the stones found in the vacinity for later building.
Thanks isobel -- I recall that you were kind enough to look at "the Shrewton erratic" a couple of years ago -- but assume you never got round to looking at the stone in the Blind House wall.
re Avebury, I'm sure there was a lot of "stone stealing" from ancient monuments -- indeed the records indicate just that. Natural enough to take stones from anywhere handy -- it still happens today.
Mind you, I still think there are too many stones missing from Stonehenge for around 80 or so to have been pinched. I'll stick to my theory that they never were there in the first place...
It does not look very preselite to me.
My guess is some sort of fg limestone-look at the sharp botton edge. It has been worked the rectanlinear pattern on the surface looks very suspect.
GCU in two minds
You may well be right. I don't think it looks like a spotted dolerite either -- but it could be a rhyolite or one of the other dolerites. They give very sharp edges. Are there bluish limestones to the west? I recall reading about such things around the Mendips -- with ref to Stanton Drew? And there is this wonderful bluish translucent rock near St David's which I called "halleflinta" when I was a student. Maybe that's a long shot! A pity I didn't have my little bottle of hydrochloric acid with me when I was in Shrewton....
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