The BGS Lexicon of Named Rock Units — Result Details

Computer Code: LTK  Status Code: FORMAL ENTRY 
Preferred Map Code:  
Age or Age Range: [ TR ] RHAETIAN  to [  ]  
Lithological Description:
Includes Cotham Member (grey and grey-green shales and siltstones) and Langport Member (porcellanous limestone below, calcareous mudstone above). 
Definition of Lower Boundary:
Placed at base of Cotham Member, sharp, commonly channeled on the Westbury Formation. 
Definition of Upper Boundary:
Placed at top of Langport Member, where there is a sharp but conformable junction with the overlying 'paper shale' of the "Blue Lias". 
Thickness:
1-10m 
Geographical Limits:
Present throughout the United Kingdom. 
Parent Unit: Parent Unit Code:
PENARTH GROUP  PNG
Previous Name(s): Previous Code(s):
none recorded or not applicable none recorded or not applicable
Alternative Name(s):
none recorded or not applicable
Stratotypes:
Type Area  Lilstock, west Somerset. 
Reference Section  Immediately north of Lavernock Point, south Glamorgan. 
Reference Section  Lilstock, west Somerset. 
Reference(s):
Waters, R A and Lawrence, D J D, 1987. Geology of the South Wales Coalfield - Part III: the country around Cardiff. Memoir of the British Geological Survey, Sheet 263. (England and Wales). 
Warrington, G, Audley-Charles, M G, Elliott, R E, Evans, W B, Ivimey-Cook, H C, Kent, P E, Robinson, P L, Shotton, F W, and Taylor, F M. 1980. A correlation of the Triassic rocks in the British Isles. Special Report of the Geological Society of London, No.13. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
Map Code Sheet Name
342
264
127
141
142
341

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