A compilation of images of native Cornish rocks, igneous and metamorphic, granites and slates, with interesting natural patterns and textures, found in various stone walls of buildings in St Ives, Cornwall in England.
https://natureinfocus.blog
Jessica's Nature Blog 
A fascinating collection!
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Thank you, CentralOhioNature.
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Fascinating, Jessica. Is the tar-like black stuff (e.g. Stone Wall 7 & 8) a type of rock or some kind of lichen?
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Hi, Jo. The black tar-like stuff is in fact – black tar-like stuff! I think that at one time the wall may have been covered with bitumen or tar, perhaps as weatherproofing. Over time most of it must have fallen off and the wall subsequently re-pointed. It does look like lichen though. High on seashore rocks there is a black lichen called Verrucaria maura which is dull black and said to be often mistaken for dried stranded oil.
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Haha, there’s always a simple answer! Thanks, Jessica. 🙂
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