The BGS Lexicon of Named Rock Units — Result Details

Shellag Formation

Computer Code: SHLAG Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Glacially technically deformed complex sequence of diamictons, gravels and shelly sands. It is dominated by material derived from offshore within the Irish Sea basin, and the Formation includes rafts of marine sediment.
Definition of Lower Boundary: The base of the Shellag Formation rests on sand, gravel and diamicton of northern origin forming the top of the Kindroughad Formation.
Definition of Upper Boundary: Overlain unconformably by the Orrisdale Formation.
Thickness: c.50m (but glacitectonically thickened by folding and repeated by faulting) at its type section.
Geographical Limits: The Isle of Man (50K sheets 36, 45, 46 and 56).
Parent Unit: Irish Sea Coast Glacigenic Subgroup (ISCG)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Type Section  Coastal cliff section at Shellag Point, 4km north of Ramsey, on the eastern side of the Isle of Man. Chadwick, R A, et al. 2001. 
Chadwick, R A, Jackson, D I, Barnes, R P, Kimbell, G S, Johnson, H, Chiverell, R C, Thomas, G S P, Jones, N S, Riley, N J, Pickett, E A, Young, B, Holliday, D W, Ball, D F, Molyneux, S G, Long, D, Power, G M and Roberts, D H. 2001. Geology of the Isle of Man and its offshore area. British Geological Survey Research Report, RR/01/06. 
Thomas, G S P. 1977. The Quaternary of the Isle of Man. 155-179 in Kidson, C and Tooley, M J (editors), The Quaternary of the Irish Sea. Geological Journal Special Issue [Liverpool: Seel House Press.] 
Thomas, G S P. 1999. Northern England. 91-98 in Bowen, D Q (Editor), A revised correlation of Quaternary and Neogene deposits in the British Isles. Geological Society Special Report No.23. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: