While we are on about erratics, giant and otherwise, let's celebrate the Ogof Golchfa "giant erratic" which sits prominently on the raised beach rock platform, embedded in Devensian till. This one is actually quite celebrated already, since it is used by the geocaching community as one of the key North Pembrokeshire locations. Note the little box in the photo, which contains trinkets and other bits and pieces of memorabilia.........
The boulder, which is well rounded, has dimensions 2m x 1.40m x 1m, and it's made of a very coarse dark coloured gabbro -- almost certainly from St Davids Head, around 5 km to the NNW.
Some of the old geologists who visited this site thought that the big well-rounded erratics on the rock platform are embedded in the raised beach, and indeed Leach thought that they are "cemented" into position. Although I could see no unambiguously cemented material at the base of the raised beach, I have some sympathy with this view, and on balance I agree with them that these boulders -- like those at Whitesands -- were already in position when they were incorporated into the raised beach shingle and pebbles. So we have evidence of TWO glaciations at Ogof Golchfa.........
5 comments:
Love the ?local? (or anthropo - transported?) flora......
Talking of Giant Erratics, Wiltshire - based farmer Tim Daws is reputed to be embedding himself somewhere in the Preselis without so much as a Severn Bridge passport. Probably neither a Welsh not a glacial geomorphology speaker. May be wearing MPP - approved human transport prejudicial camouflage.
Well, it's a free country. Tim is very welcome to enjoy the beauties of the Preseli Hills, just like everybody else. And if he wants to pop in and take a look at my Bluestone Museum, the door will be open and we don't even charge an entry fee.........
Tim's secret visit is not all that secret -- since it is all over Twitter. He's doing the bluestone fantasy tour -- Rhosyfelin, Waun Mawn and probably Carn Goedog too. In perfect weather. The extra publicity will of course delight MPP and the rest of the gang.
Tim has now left the building:- area of the fantasy ProtoStonehenge as proclaimed so unsuccessfully by Maestro Pied Piper MPP. He's back on home turf, near Devizes.
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