The BGS Lexicon of Named Rock Units — Result Details

Reisgill Burn Till Formation

Computer Code: REDR Preferred Map Code: RB
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Dominantly calcareous glacial diamicton containing clasts of Orcadian Devonian rocks, Mesozoic erratics and Quaternary shells. Note that the partially synonymous term Lybster Formation (Hall and Whittington, 1989) was pre-used by the BGS to cover Middle Devonian strata (Lybster Flagstone Formation). The unit defined by Hall and Whittington included Late glacial peats and gellifluctates, but only true glacial sediments are included in the Reisgill Burn Till Formation. To date only one Member, the Forse Till Member, has been recognised, but further survey work in Caithness may reveal more.
Definition of Lower Boundary: Unconformable on bedrock or on the Dunbeath Till Formation.
Definition of Upper Boundary: Taken at the base of overlying Holocene strata.
Thickness: At least 25m
Geographical Limits: Caithness and Sutherland northeast of a line between Reay and Berridale (1:50 000 Sheets 115E and W, 116 E and W, 110). Note that this unit does not equate with the Quaternary Lybster Formation of Hall and Whittington (1989) and the term Lybster [Flagstone] Formation is pre-used by the BGS to include rocks of Mid Devonian age.
Parent Unit: Banffshire Coast and Caithness Glacigenic Subgroup (BCD)
Previous Name(s): Lybster Formation (-2998)
Alternative Name(s): Caithness Shelly Till
Stratotypes:
Type Section  Stream section at Ellanmore, Reisgill Burn. Hall and Whittington, 1989, p.315. 
Type Area  Sections in the Reisgill Burn, inland of Lybster, Caithness. Hall and Whittington, 1989. 
Reference(s):
Hall, A M and Whittington, G. 1989. Late Devensian glaciation of southern Caithness. Scottish Journal of Geology, Vol.25, 307-324. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S116 S110 S115 S115 S116 S116