The BGS Lexicon of Named Rock Units — Result Details

Marehill Clay Member

Computer Code: MHC Preferred Map Code: MhC
Status Code: Full
Age range: Aptian Age (KP) — Aptian Age (KP)
Lithological Description: Dark grey, locally glauconitic, silty clay.
Definition of Lower Boundary: The lower boundary is taken at the upward change from mostly well-sorted fine-grained sands (locally iron-cemented at top) of the Pulborough Sandrock Member to silty clay (or clayey sand) of the Marehill Clay Member.
Definition of Upper Boundary: The top is taken where there is an upward change from silty clay of the member into well-sorted medium to coarse sands of the Folkestone Formation. The contact is generally sharp, but rarely exposed.
Thickness: 2 to 35m.
Geographical Limits: Southwestern and western Weald.
Parent Unit: Sandgate Formation (SAB)
Previous Name(s): Previously part of Undifferentiated Sandgate Beds (-4794)
Mare Hill Clay (-4191)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Old sandpit at Pulborough, near Marehill. The most characteristic lithology is a dark grey, blocky weathering, silty clay, which is locally sandy or glauconitic, in places extremely glauconitic; dark grey and lilac clayey silts or waxy clays occur in places. Humphries (1964, p.31) noted yellow, white and brown sandy clay in the Marehill quarry, the type locality [TQ 0647 1864], where the clay was stripped off as overburden during extraction of sand from the Pulborough Sandrock. Humphries (1964, p.51) measured a section in this pit when both the Marehill Clay (about 3 m) and the Pulborough Sandrock (about 5.6 m) were better exposed. 
Reference(s):
Kirkaldy, J F. 1933. The Sandgate Beds of the Western Weald. Proceedings of the Geologists' Association, Vol.44, 270-311. 
Bristow, C R and Wyatt, R J. 1983. Geological notes and local details for 1:10 000 sheets TQ01NW, NE, SW and SE (Pulborough and Storrington). British Geological Survey Technical Report, WA/VG/83/03. 
Bristow, C R. 1991. Geology of the Petersfield District, Hampshire. Explanation of 1:10,000 Geological sheets SU72NW, 72NE, 72SW, 72SE, 82NW and 82SW. British Geological Survey Technical Report, WA/91/24. 
Humphries, D W. 1964. The stratigraphy of the Lower Greensand of the south-west Weald. Proceedings of the Geologists' Association, Vol.75, 39-59. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E300 E316 E317 E332