The BGS Lexicon of Named Rock Units — Result Details

Gala Unit 7

Computer Code: GAL7 Preferred Map Code: GALA7
Status Code: Full
Age range: Aeronian Age (SA) — Aeronian Age (SA)
Lithological Description: Graded beds that may include wacke sandstone, siltstone and mudstone in variable proportion, interpreted as turbidites.
Definition of Lower Boundary: Southern faulted boundary: Port Logan Fault (Rhins of Galloway); Cambret Fault (Wigtown Peninsula); Laurieston Fault east of Wigtown Bay. Stratigraphical lower boundary with underlying Moffat Shale Group (of Ordovician to Silurian age up to sedwickii - halli Biozones).
Definition of Upper Boundary: Northern faulted boundary southernmost splay of Drumbreddan Fault (Rhins of Galloway); Pibble Fault (Kirkcowan and Wigtown); Garheugh Fault (to the north-east).
Thickness: c. 1850m of near vertical strata
Geographical Limits: Mapped from Port Logan Bay on the Rhins of Galloway (Sheet 1/3) to Peebleshire (Sheet24E). Correlation with Central Belt turbidites of Llandovery age in the Ards Peninsula, Northern Ireland.
Parent Unit: Gala Group (GALA)
Previous Name(s): Gala Group (GALA)
Intermediate And Garnetiferous Greywacke Groups (-273)
Queensberry Grits (-1552)
Alternative Name(s): Mull Of Logan Formation Of The Rhins Of Galloway (Sheet 1/3)
Stratotypes:
Reference Section  Discontinuous exposure of the lower part of Gala 7 from the south-east side of Skeoch Hill to the summit of Bishop Forest Hill, Shawhead, 10 km. west of Dumfries. 
Reference Section  Referred to four informal members, the Cairnie Finnart, the Daw Point, Duniehinnie and Chair members; coastal section north of Port Logan Bay, 8.5 km. SSW of Sandhead, Rhins of Galloway, Sheet 1/3. Stone, 1995. 
Reference(s):
Lapworth, C, 1871. On the Lower Silurian rocks in the neighbourhood of Galashiels. Transactions of the Edinburgh Geological Society, 2, 46 - 58. 
Walton, E K. 1955. Silurian greywackes in Peeblesshire. Proceedings of the Royal Society of Edinburgh, B65, 327-357. 
Stone, P, 1995. Geology of the Rhins of Galloway district. Memoir of the British Geological Survey, Sheets 1 & 3 (Scotland). 
Barnes, R P, Anderson, T B and McCurry, J A . 1987. Along-strike variation in the stratigraphical and structural profile of the Southern Uplands Central Belt in Galloway and Longford Down. Journal of the Geological Society, 144, 807 - 816. 
McMillan, A A. 2002. Geology of the New Galloway and Thornhill District. 2002. Memoir of the British Geological Survey. Sheets 9W and 9E (Scotland). 
Peach, B N and Horne, J. 1899. The Silurian Rocks of Britain, Volume 1. Scotland. Memoir of the Geological Survey of the United Kingdom. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S001 S003 S004 S004 S005 S009 S009 S016 S024 N29 S015