Gloucestershire Geology Trust


Barry Harbour Limestone [Lower Dolomite]

Early Carboniferous (Courceyan-Chadian)

Carboniferous Limestone
Barry Harbour Limestone

Well bedded to massive, compact, finely to coarsley cystalline dolomites, normally blue-grey in colour, but can be stained red-brown-purple. There are a few shale partings. Fossils are comparatively rare due to extensive dolomitisation.

Upper Boundary
Taken as a conformable upward passage into the overlying Gulley Oolite (Crease Limestone) where iron mineralisation and dolomitisation overlap. More easily identified in the north of the outcrop where ron mineralisation is more apparent.

Lower Boundary
Taken as the base of the dolomitic limestone, where it overlies dark shales and thinly bedded limestone, sandstone and shale interbeds of the Avon Group (Lower Limestone Shale)

Representative Sites
Tintern Quarry
Shakemantle Quarry
Nags Head Quarry

Information on lithology and boundaries taken from the British Geological Survey Lexicon of Named Rock Units
and BGS Memoirs.


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