Lawrence, D. J. D. 1990. Limestone Landscapes — a geodiversity audit and action plan for the Durham Magnesian Limestone Plateau. British Geological Survey open report OR/09/007.
Blackhall Rocks [NT 468 395]
Coastal cliffs and foreshore
Owned by —
Excellent exposures of three geological units: the Heselden Dene Stromatolite in the Ford Formation, the Roker Dolomite Formation and the Seaham Residue and Formation.
Biodiversity interest. The exposure is very distinctive and is of great interest. When the tide is out the beach exposure is excellent and worthwhile visiting.
Proposed action
Existing designations NNR SSSI GCR LNR MAGic DWT
Existing on site interpretation Information boards on cliff top describe 'The rocks under your feet' and 'Grassland life' a third board about stacks is now somewhat out-of-date since demolition of arch in 2004
Major geodiversity interest The coastal cliffs and shore platforms at Blackhalls Rocks constitute the largest and best exposure of the Hesleden Dene Stromatolitic Biostrome (?45m) together with the whole of the overlying cycle EZ2 Roker Dolomite Formation (?16m) and much of the Seaham Formation. The beds exposed at Blackhall Rocks reveal abundant stromatolitic and oolitic dolomites that are associated with brecciation, with a comglomerate containing shelly material exposed in the core of the anticlinal structure making up the section
Biodiversity interest Unusual seepage flushes from calcium-rich seepage waters where glacial deposits meet underlying bedrock. Large area of common rock rose centred on Blue House Gill.
Other heritage links
Additional comment Can link to interpretation at Noses's Point.
Date of photography 2004