The BGS Lexicon of Named Rock Units — Result Details

Stockdale Rhyolite Formation [Obsolete Name And Code: Replaced By YRL]

Computer Code: SRH Preferred Map Code: SRh
Status Code: Index Level
Age range: Cautleyan Stage (OU) — Cautleyan Stage (OU)
Lithological Description: Pink to pale grey flow-banded or flow-folded rhyolite with lithophysae locally present. Contrasts with sedimentary formations above and below.
Definition of Lower Boundary: At junction with calcareous siltstones of Stile End Formation.
Definition of Upper Boundary: At junction with limestones of the Applethwaite Formation (Mcnamara, 1967), at several localities the formation is overlain by a conglomerate of rhyolite pebbles.
Thickness: Maximum thickness c. 190 metres, thins and dies out westwards over a distance of 2 km. Continues eastwards to Shap, but exposure is discontinuous and lateral variation uncertain.
Geographical Limits: Not defined.
Parent Unit: Coniston Limestone Group [Obsolete Name And Code: Use DNT] (COL)
Previous Name(s): Yarlside Rhyolite (-3693)
Stockdale Rhyolite (-542)
Alternative Name(s): Yarlside Volcanic Formation
Stratotypes:
Type Area  Series of exposures on hillside, west of Stockdale Beck, Sheet 39, Kendal. 
Reference(s):
Lawrence, D J D, Webb, B C, Young, B and White, D E. 1986. The geology of the Late Ordovician and Silurian rocks (Windermere Group) in the area around Kentmere and Crook. Includes map, 1:25,000 series, Parts of Sheets NY40 and SD49 Kentmere and Crook, Solid and Drift Geology. Report of the British Geological Survey, 18/5. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E039