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Coralline Oolite Formation

  (Redirected from Coral Rag Formation)

The Coralline Oolite Formation is a limestone formation of Oxfordian (Upper Jurassic) age, found in the Cleveland Basin of North Yorkshire, England.[1]

Coralline Oolite Formation
Stratigraphic range: Oxfordian
Unit ofCorallian Group
Sub-unitsCoral Rag Member, Yedmandale Member, Hambleton Oolite Member, Malton Oolite Member, Birdsall Calcareous Grit Member, Middle Calcareous Grit Member, Hildenley Limestone Member
UnderliesUpper Calcareous Grit Formation, Ampthill Clay Formation, Hunstanton Formation
OverliesLower Calcareous Grit Formation, Oxford Clay Formation
Thickness36–60 m
RegionNorth Yorkshire
ExtentCleveland Basin
Type section
LocationFiley Brigg, Filey

Coral Rag MemberEdit

Coral Rag as building stone: the Saxon tower of St Michael at the Northgate, Oxford

The rock forms some of the hills around Oxford and was once used as building stone. Coral rag can be seen in some of the oldest buildings in that city, including the Saxon tower of St Michael at the Northgate, St George's Tower of Oxford Castle and the mediaeval walls of the city.[2]

Hambleton Oolite MemberEdit

This ooidal limestone lies above either the Yedmandale Member or the Lower Calcareous Grit Formation. It is overlain by either the Middle Calcareous Grit or Malton Oolite Members. It is distinguished from the latter by its smaller grain-size and poorer sorting.[3]


  1. ^ British Geological Survey. "Coralline Oolite Formation". BGS Lexicon of Named Rock Units.
  2. ^ "Strategic Stone Study: A Building Stone Atlas of Oxfordshire". English Heritage. March 2011. Retrieved 23 April 2015.
  3. ^ British Geological Survey. "Hambleton Oolite Member". BGS Lexicon of Named Rock Units. Retrieved 4 November 2018.