The BGS Lexicon of Named Rock Units — Result Details

Bonaly Group [Obsolete: use BNY, WKH]

Computer Code: BOG Preferred Map Code: notEntered
Status Code: Full
Age range: Devonian Period (D) — Devonian Period (D)
Lithological Description: [Obsolete: use BNY, WKH] Feldspar-phyric andesites and olivine-basalts; local rhyolites.
Definition of Lower Boundary: Drawn at the base of the Bonally Group where feldspar-phyric andesites rest upon purplish-grey feldspar-phyric basalts of the Warklaw Group.
Definition of Upper Boundary: Drawn at the conformable upward passage of the Bonally Group where fine- grained andesites are overlain by pink aphanitic rhyolite with flow banded platy weathering of the Bell's Hill and Howden Burn Group.
Thickness: Approx. 600 metres.
Geographical Limits: Midland Valley of Scotland.
Parent Unit: none recorded or not applicable
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  The Pentland Hills, 2 kms south of Swanston, Edinburgh. 
Reference(s):
Mykura, W, 1960. The Lower Old Red Sandstone igneous rocks of the Pentland Hills. Bulletin of the Geological Survey of Great Britain, No.16, 131-155. 
Browne, M A E, Smith, R A and Aitken, A M. 2001. A lithostratigraphical framework for the Devonian (Old Red Sandstone) rocks of Scotland south of a line from Fort William to Aberdeen. Version 3. British Geological Survey Research Report RR/01/04. 
Mitchell, G H. 1962. The geology of the neighbourhood of Edinburgh. (Explanation of Sheet 32) Third Edition. (Reprinted 1980). Memoir of the Geological Survey of Great Britain (Scotland). 
Cameron, I B and Stephenson, D, 1985. British Regional Geology: The Midland Valley of Scotland (3rd Edition). (London: HMSO for British Geological Survey). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable