The Heron Group is a Triassic lithostratigraphic group (a sequence of rock strata) beneath the central and northern North Sea which is composed of alluvial deposits.Stratigraphical Chart of the United Kingdom:Northern Britain, British Geological Surveyhttp://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=HERO (BGS on-line lexicon of rock units)
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