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Tuesday, 20 January 2015

Other Sleek Stone Erratics (1)

Stone No 4 appears to be different from the others -- and I wonder if it is a diorite?  I'd like to take a look at it in the company of an expert geologist, when the sun is shining!

It has the same greenish colouring, but the texture is much coarser, and there don't seem to be obvious phenocrysts -- just a jumble of minerals, many of which have dark elongated crystals.....  opinions please?





And below is a photo of some of the beach pebbles that are scattered about in abundance all over the beach to the north of the Sleek Stone.


Some of these (the greenish and bluish speckled pebbles) look familiar -- and are related to the Giant Erratics -- but we also have a pebble of Cambrian red sandstone here, and the larger pebble to the right of it looks as if it might be gabbro from St David's Head.

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