Freshfield Lane

Also within

East Sussex CountyWest Sussex County High Weald Scenic Area

Condition (Natural England)

Geology & landscape

Mining / Industrial: Quarry · Geological Period: Cretaceous, Precambrian · Rock Type: Sandstone

Landscape processes: Fluvial

Description

Description The Freshfield Lane Brickworks is a working quarry about two kilometres south of Horsted Keynes. The pit provides exposures of the Upper Wadhurst Clay Formation Lower Hastings Beds Group and Lower Tunbridge Wells Sand, Grinstead Clay and Basal Upper Tunbridge Wells Sand Formations Upper Hastings Beds Group, of Lower Cretaceous, Wealden age. The Upper Wadhurst Formation comprises 15 metres of dark grey laminated mudstones with thin lenticular siltstones and bioclastic limestones containing a fauna of bivalves, gastropods and ostracods. The High brooms Soil Bed consists of two soil beds developed within the top eight metres of the formation. They contain rhizomes and rootlets of the pteridophyte Equisetum lyellii in inferred growth position. The top six metres of the formation consist of varicoloured red, green and grey clays regarded as having a pedogenic origin. Within this horizon a thin sharp based sandstone contains a well preserved vertebrate fauna. Much of the overlying Lower Tunbridge Wells Formation is unexposed. The Top Lower Tunbridge Wells Pebble Bed is seen and contains extrabasinal Precambrian, Palaeozoic and Mesozoic clasts. This part of the succession represents the shallowing of the lake followed by the development of a fluvial plain resulting from uplift taking place in the London area. Above the Lower Tunbridge Wells Formation, the upper and lower members of the Grinstead Clay Formation enclose the Cuckfield Stone Member. This is followed by a sandstone forming the lowest part of the Upper Tunbridge Wells Sand Formation. The Grinstead Clay represents a return to lacustrine conditions. The Cuckfield Stone consists of trough cross bedded sandstone and represents an erosive fluvial channel cut into the underlying lake muds of the lower Grinstead Clay. Colour mottling in the upper part of the upper Grinstead Clay reflects the re establishment of intermittent emergence and the establishment of a lagoonal or alluvial plain – the deposition of the Upper Tunbridge Wells Formation reflecting the reactivation of uplift in the London area and the reestablishment of a fluvial plain. The section, while largely complete from the upper Wadhurst Clay to basal Upper Tunbridge Wells Formation, is complicated by faulting and cambering. Nevertheless, it is internationally important for palaeoenvironmental, provenance and palaeogeographical studies and provides extensive sections throughout two of the Wealden sedimentary megacycles.