Description:

A flaggy,  sandy,  carbonate mudstone. 

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This muddy limestone varies across the area it crops out:

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• grey, weathering brown

 

• or - flaggy, variably sandy medium to coarsely bioclastic grainstone.

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Environment of Deposition:

The Forest Marble is a complex association of vertically and laterally changing facies.   These are interpreted to represent environments ranging from subtidal-intertidal fully marine sand shoals and hard substrates colonised by corals, to mud flats and tidal channels associated with coastal swamps. 

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Upper Boundary:

Generally mudstone in the upper part of the Formation, overlain sharply and non-sequentially by ooidal shelly wackestone/packstone of the Cornbrash Formation.

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Lower Boundary:

A grey to brown variably sandy medium to coarsely bioclastic grainstone or packstone, resting with erosive, commonly channelled, disconformity on the White Limestone Formation.

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Index Fossils:

Retrocostatum Zone to Discus Zone

 

Landform contribution:

Generally forms plateaux behind escarpments formed by basal limestone of the formation or underlying limestone formations.

 

Thickness:

10-30 m

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See it in Oxfordshire:

Shipton-on-Cherwell Quarry (BGS reference section)

Kirtlington Quarry

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Type area:

Wychwood Forest, Oxfordshire (i.e. the area approximately from Burford to Bladon, and northwards to the River Evenlode (Smith, 1812, unpublished stratal tables; see Arkell, 1933)