The BGS Lexicon of Named Rock Units — Result Details

How Hill Member

Computer Code: HOWH Preferred Map Code: notEntered
Status Code: Full
Age range: Quaternary Period (Q) — Quaternary Period (Q)
Lithological Description: The How Hill Member is composed of sand and predominantly flint gravel. It is characterised by c.30-40 per cent white or colourless quartzose rocks, persistent small percentages of Carboniferous and Rhaxella chert and traces of Spilsby Sandstone, Greensand Chert and both felsic and mafic volcanic rocks.It is marine in origin.
Definition of Lower Boundary: Unconformable on Chalk bedrock, but may also overlie Norwich Crag Formation sands or Dobbs Plantation Member of the Wroxham Crag Formation.
Definition of Upper Boundary: At surface or overlain unconformably by sands or till of the Happisburgh Formation (previously known as Corton Formation).
Thickness: Probably in excess of 10m, but information is lacking.
Geographical Limits: North-eastern East Anglia but imperfectly known probably restricted to the area north and north-east of Norwich. Not depicted separately on BGS maps but included within the Crag Group.
Parent Unit: Wroxham Crag Formation (WRCG)
Previous Name(s): Bure Valley Beds And Weybourne Crag (-4711)
Alternative Name(s): none recorded or not applicable
Type Section  Trial pits on north-west side of How Hill Rose et al, 1996 
Rose, J and others. 1996. Pre-glacial Quaternary sediments, How Hill, near Ludham, Norfolk, England. Bulletin of the Geological Society of Norfolk, Vol. 45, 3-28. 
Rose, J, Moorlock, B S P and Hamblin, R J O. 2001. Pre-Anglian fluvial and coastal deposits in Eastern England: lithostratigraphy and palaeoenvironments. Quaternary International, 79, 5-22. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable