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Earth Science Conservation Review

Summary Full report
Barony GlenLondonderry
Site number:301File Number:C70
ESCC:EO
Locality Type:River bank, Stream section Status: local interest
Grid Reference: C732016 1 km square
Google maps: 54.85724,-6.86018
County: LondonderryCouncil area:Mid Ulster District Council
Period:Carboniferous
Stages:Tournasian
Lithostrat:Altagoan Formation, Drumard Member, Tyrone Group
Site Description
image: 0301a.jpg Lower part of Barony Glen, Co.Londonderry, looking east, showing dominant red-purple colour of most of the rocks of the Drumard Member of the Altagoan Formation.
Lower part of Barony Glen, Co.Londonderry, looking east, showing dominant red-purple colour of most of the rocks of the Drumard Member of the Altagoan Formation.
Highlights:
The deeply incised valley of Barony Glen exposes a virtually continuous section through the Drumard Member of the Altagoan Formation.

Description:
Exposures of the Drumard Member occur in an almost continuous section over some 320m of stream bed and in fresh and clean bank sections in Barony Glen. The stream course is steeply inclined falling from an altitude of about 460m, at the base of the overlying Palaeogene (Tertiary) basalt lavas that cap White Mountain and Mullaghmore, to an altitude of 360m just east of Barony Bridge where the last exposure occurs.
image: 0301b.jpg The lowest, most westerly exposures of the Drumard Member in Barony Glen consist of thick fluvial sandstones and green-grey (purple-red stained) mudstones and siltstones.
The lowest, most westerly exposures of the Drumard Member in Barony Glen consist of thick fluvial sandstones and green-grey (purple-red stained) mudstones and siltstones.


Exposures consist of a wide variety of lithologies with purple- brown shades dominating the rocks, although green to pale grey and purple-red colours occur sporadically. Evidence of pedogenesis (soil formation) abound, in particular the formation of carbonate nodules and discrete pedogenic limestone bands.
image: 0301c.jpg The fallmaker here is a yellow-purple sandstone; hammer-head rests on an intra-formational conglomerate comprising reworked nodules of pedogenic carbonate in green-grey silty shale.
The fallmaker here is a yellow-purple sandstone; hammer-head rests on an intra-formational conglomerate comprising reworked nodules of pedogenic carbonate in green-grey silty shale.
Purple-brown, frequently unbedded mudstones and siltstones dominate the sequence with parallel bedded sandstones showing the periodic influence of fluvial action on the land surface at that time.
image: 0301d.jpg Most easterly major waterfall in Glen comprises well-bedded purple-red sandstones, fawn sandstones, and purple and green mudstones overlying unbedded purple-red palaeosols with pale yellow carbonate beds; hammer leans against pedogenic calcrete profile.
Most easterly major waterfall in Glen comprises well-bedded purple-red sandstones, fawn sandstones, and purple and green mudstones overlying unbedded purple-red palaeosols with pale yellow carbonate beds; hammer leans against pedogenic calcrete profile.
Thin layers of green mudstone were sent for palynological analysis but were found to be barren.
image: 0301e.jpg Interbedded and faulted, fawn, thin calcareous sandstones and green (primary) mudstones overlying purple-red mudstones.
Interbedded and faulted, fawn, thin calcareous sandstones and green (primary) mudstones overlying purple-red mudstones.
image: 0301f.jpg Detail of same locality showing green mudstone - fawn sandstone interval.
Detail of same locality showing green mudstone - fawn sandstone interval.
The strata are disposed almost horizontally in Barony Glen and at least 100m of the Drumard Member is exposed here.
Notes:
For information on other sites in Subarea-12 see Key Site 1185 - Subarea-12; Draperstown-Glenshane Pass-Limavady.
Keywords
Rocks:Limestone, Mudstone, Sand, Sandstone, Siltstone
Relations:Fluvial sediments
Paleoenv:alluvial plain
Measurements
Length:320 mWidth:Height:
Depth:Area:  
Map(s): GSNI (1981) 1:50,000 Solid Geology of Sheet 12 (Limavady);
GSNI (1995) 1:50,000 Solid Geology of Sheet 26 (Draperstown).
Record type: ESCR report    
Entered by: Doughty, P.J.
Last updated:23 Dec 2003
 Enlander, I., Dempster, M. & Doughty, P., 2026. Barony Glen, County Londonderry, site details. [In] Earth Science Conservation Review.
https://www.habitas.org.uk/escr/site.php?item=301. Accessed on 2026-11-05.

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