The BGS Lexicon of Named Rock Units — Result Details

Newton St Cyres Breccia Formation

Computer Code: NSBR Preferred Map Code: NSBr
Status Code: Full
Age range: Permian Period (P) — Permian Period (P)
Lithological Description: Reddish brown, mainly fine-grained breccia; clasts (mostly < 5cm) of shale, slate, hornfels, chert, potassium feldspar (murchisonite), vein quartz, quartz-porphyry, acid lava and tuff, microgranite and tourmalinised igneous rocks. Locally well cemented. Local sandstone beds. Sub-vertical sandstone bodies.
Definition of Lower Boundary: Correlates with Heavitree Breccia of Exeter area. Rests on Crediton Breccia, locally with a scarp at the junction. Distinguished from Crediton Breccia by more sandy matrix, greater degree of cementation and presence (increasing towards the top) of potassium feldspar (murchisonite).
Definition of Upper Boundary: Passes gradationally upwards and laterally into the Shute Sandstone.
Thickness: 180m southwest of Newton St Cyres, 10m at Creedy Barton (SX 865 995).
Geographical Limits: Present in the eastern Crediton Trough around the limbs of a synclinal structure from Newton St Cyres in the south, to Trobridge House. [SX 835 979] in the west, to near Shute [SS 890 001] in the north.
Parent Unit: Exeter Group (EXE)
Previous Name(s): St Cyres Beds (-2344)
St Cyres Breccias (-4229)
Alternative Name(s): Heavitree Breccia
Stratotypes:
Type Area  Road cuttings in Newton St Cyres to east and west of the village. 
Reference(s):
Edmonds, E A, Wright, J E, Beer, K E, Hawkes, J R, Fenning, P J, Freshney, E C, Lovelock, P E R, McKeown, M C, Ramsbottom, W H C and Williams, M. 1968. Geology of the country around Okehampton. Memoir of the Geological Survey of Great Britain, Sheet 324 (England and Wales). 
Hutchins, P F, 1963. The Lower New Red Sandstone of the Crediton Valley. Geological Magazine, Vol.100, 107-128. 
Laming, D J C, 1982. The New Red Sandstone. "In" Durrance, E M and Laming, D J C, (Editors). The Geology of Devon, p.148-177. 
Scrivener, R C. 1988. Geology of the Newton St Cyres district (Devon). 1:10,000 Sheet SX89NE. British Geological Survey Technical Report, WA/88/5/ 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable