Corallian limestone/Lias Group separation map

Area where aquifer and shale/clay are present	North Yorkshire Southern England Note that for the purposes of drafting this separation map the maximum depth of the Corallian aquifer is taken to be 400 mbgl based on the recommendations in the UK TAG report. More information about this can be found in the methods section
Thickness of intervening strata	North Yorkshire: about 50 to 300 m Southern England: about 100 to 500 m
Lithology of intervening strata	North Yorkshire: permeable Ravenscar Group; low permeability Kellaways Formation (clay); Oxford Clay Formation (clay); Osgodby Formation (clay) Southern England: permeable Great Oolite Group and Inferior Oolite Group (principal aquifer); low permeability Kellaways Formation (clay); Oxford Clay Formation (clay); Osgodby Formation (clay)
Other major aquifers in the area	North Yorkshire: Chalk (above); Triassic sandstone; Magnesian limestone; Carboniferous limestone (all below) Southern England: Chalk; Lower Greensand (both above); Triassic sandstone; Magnesian limestone; Carboniferous limestone (all below)
Other shales or clays in the area	North Yorkshire: Kimmeridge Clay Formation; Ampthill Clay Formation (both above); Bowland Shale Formation; Craven Group (both below) Southern England: Kimmeridge Clay Formation; Ampthill Clay Formation (both above)
Aquifer map	Corallian limestone principal aquifer
Shale/clay map	Kimmeridge Clay and Ampthill Clay formations shale/clay unit

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