THREE OSTRACOD-MUSSEL BANDS IN THE COAL MEASURES (WESTPHALIAN) OF NORTHUMBERLAND AND DURHAM

Abstract
Summary: The stratigraphy, palaeontology and depositional environments of three ostracod-mussel bands in the Lower and Middle Coal Measures of Northumberland and Durham are described. The fossils of the Brockwell Ostracod Band, of the Carbonicola communis Zone, make up three faunal phases preserved in shale and mudstone. The Hopkins Band, in the lower Anthraconaia modiolaris Zone, is persistent over a wide area of the coalfield and shows six distinct faunal phases within the band (Pollard, 1966). The Claxheugh Shell Bed of the Upper Anthracosia similis-Anthraconaia pulchra Zone has a rich arthropod fauna preserved with non-marine mussels in an ironstone matrix. A detailed analysis of the non-marine bivalves in relationship to the petrology and chemistry of the sediments of the Hopkins Band elucidates the conditions of its formation. It is concluded that both the Brockwell Ostracod Band and the Hopkins Band were deposited in large lagoonal areas marginal to a coal swamp; the Claxheugh Shell Bed was formed in a more temporary pool within the complex of the Coal Measures delta.