Philpot's and Hook Quarries

Also within

West Sussex County High Weald Scenic Area

Condition (Natural England)

Geology & landscape

Mining / Industrial: Quarry · Geological Period: Precambrian · Rock Type: Conglomerate, Ironstone, Sandstone, Siltstone

Description

Area, 2.39 ha. 5.91 ac. Description Philpots Quarry This quarry exposes the upper parts 4m of the Ardingly Sandstone Member of the upper Lower Tunbridge Wells Sand Formation and the lower member of the Grinstead Clay Formation 8.2 metres capped by the base of the Cuckfield Stone Member upper Hastings Beds Group. The fluviatile Ardingly sandstones lie on a ferruginous intraformational conglomerate, containing debris from a lateritic soil. They presently show very low angle, large scale trough crossbedding facing south south east, as at Hook one kilometre to the south. During the next decade, when quarrying returns down the west side of the pit, the heads of large gravely scoops will be transected again. Water flow down the delta fan slope was intermittent, varying from powerful horizontal laminae with current lineation to weak ripple crosslamination to nil wave ripples, often draped with trailed and burrowed or sometimes suncracked clay films. Molluscan body fossils Neomiodon, Viviparus, Unio record freshwater conditions. The bottom one metre, directly above the intraformational conglomerate, contains abundant upstanding Lycopodites in life positions, associated with small structures showing that the plants grew upwards as the sand accreted around them. Dinosaur bones are frequent in this sandstone and a headless articulated skeleton of Iquanodon has been found. Other reptiles and fish including whole Pachythrissops have also turned up. The sequence shows a depositional dip of a few degrees to the south and may be, with that at Hook, part of a 'village sized' fan. The graded Top Lower Tunbridge Wells Pebble Bed cuts horizontally and erosively across the Ardingly sandstones. It is a rich repository of Precambrian, Lower and Upper Palaeozoic and Mesozoic debris from the London Massif. Visean and Portlandian cherts, phosphatised Kimmeridgian ammonites and Portlandian glauconite can be collected, but Armorican debris is virtually absent. Above, the quarry overburden comprises more than eight metres of dark lower Grinstead clays recording salinities ranging more widely, from freshwater Equisteum lyellii in life position, Cypridea, Unio, Viviparus, etc to appreciably brackish dinoflagellates, non Cypridea ostracods, Neomiodon yielding C isotope evidence. Waterflow varied from stagnant finely laminated dark clays with unorientated plant fragments, ostracods, etc toweak clays with orientated debris to briefly strong siltstone gutter casts. A suncracked and partly oxidised sideritic ironstone records a period of exposure. Fine plant debris is common and disarticulated dinosaur bones are occasionally found near the base. With the underlying Pebble Bed, the lowest Grinstead member records the inundation of the Ardingly fan delta by a shallow lagoon, bay or lake of varying salinity, itself invaded by the Cuckfield Member sand body. The transition to the latter is shown by lenticular bedding at the top of the overburden face. With the Hook site, this is probably the most important inland exposure of the Hastings Beds Group generally, being a vital key to the provenance of their materials, their conditions of deposition and their plant and animal ecology. The scientific potential of this site is enhanced by the cliffs up to 10 metres high in nearby Chiddingly Wood. These should provide a test of the fan hypothesis advanced for the sedimentary structures here and at Hook Quarry. Though heavily encrusted with lichensand mosses, rock falls occasionally expose fresh rock. Hook Quarry An intermittently working quarry exposing three metres of the upper part of the Ardingly Sandstone Member of the upper Lower Tunbridge Wells Formation and two metres of the basal Grinstead Clay Formation upper Hastings Beds Group. Large scale low angle trough cross bedding in the fine grained Ardingly sandstones reflects a southerly palaeoslope, possibly on a 'village sized' fan delta. Sedimentary structures show that water flow down the slope varied frequently, from strong current lineation through weaker ripple cross lamination to nil asymmetrical ripples, often clay draped and surfaced with trace fossils trails and burrows and sometimes suncracks. Symmetrical wave ripples on horizontal surfaces suggest south easterly winds. Recycled Portlandian glauconite is locally abundant. The graded Top Lower Tunbridge Wells Pebble Bed cuts horizontally and erosively across the sandstone and shows the same feature as at Philpots Quarry. It is a rich repository of Precambrian, Lower and Upper Palaeozoic and Mesozoic debris from the London Massif. Visean and Portlandian cherts, phosphatised Kimmeridgian ammonites and Portlandian glauconite can be collected, Armorican debris is notably absent. On top, the Pebble Bed is moulded into large interfering wave ripples which record the increased fetch and/or storm frequency as the Grinstead transgression got under way. Above, the basal, Grinstead Clay, together with the Pebble Bed, records the inundation of the fan by a shallow lagoon, bay or lake.