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Earth Science Conservation Review
| Rahallan Townland | Fermanagh |
| Site number: | 180 | File Number: | H14 |
| ESCC: | EO | ||
| Locality Type: | Stream section | Status: | local interest |
| Grid Reference: | H147402 Centroid | ||
| Google maps: | 54.31082,-7.77413 | ||
| County: | Fermanagh | Council area: | Fermanagh & Omagh District Council |
| Period: | Carboniferous | ||
| Stages: | Asbian, Visean | ||
| Lithostrat: | Benbulben Shale Formation, Tyrone Group | ||
| Site Description | |
|---|---|
| Highlights: | |
This exposure of the Benbulben Shale Formation is in lithologies that are typical of the formation as a whole and yields superb specimens of solitary corals. | |
| Description: | |
Numerous stream sections draining the south side of Belmore Mountain are deeply incised and expose long gully sections in the Benbulben Shale. Many of them are relatively inaccessible and for this reason the section that occurs in the western boundary stream of Rahallan Townland, 6.5km east-northeast of Belcoo has been selected. There is almost continuous exposure in the stream for over 250m upstream from the road and rockhead is covered by up to 3m of till. Although the regional dip, on the south side of Belmore Mountain is to the northwest, dips in these strata, in all sections, vary enormously and there are many examples of small scale faults and minor flexuring. The rocks consist of blue-grey to dark blue-grey mudstones and shaley mudstones with occasional thin limestone beds up to 10cm thick. All lithologies are very fossiliferous, the mudstones in particular contain a profusion of crinoid and bryozoa debris and, on some surfaces, an abundance of large brachiopods. Near the south end of the section is a mudstone bed and bedding surface strewn with numerous large specimens of Siphonophyllia benburbensis; one specimen measuring almost 0.9m long. Being mostly curved specimens they appear to show no preferred orientation due to current flow. | |
| Interpretation: | |
Many other sections exist within the outcrop of this formation in Subarea-1 that also demonstrate the typical lithologies and yield the prolific macrofauna that is characteristic of the Benbulben Shale Formation. The section at Rahallan is chosen because it conforms to the typical formational description and because of its easy access. | |
| Conclusions: | |
The Rahallan section is composed of lithologies typical of this formation and also yields a prolific fauna, in particular corals, that are diagnostic of an Asbian age. | |
| Notes: | |
For information on other sites in Subarea-1 see; Key Site 1174 - Subarea-1; Derrygonnelly-Marble Arch-Cuilcagh. | |
| Keywords | |
|---|---|
| Rocks: | Mudstone |
| Fossil Groups: | Brachiopod, Coral, Crinoid, Polyzoan |
| Fossil List: | Siphonophyllia benburbensis |
| Relations: | Marine sediments |
| Access | |
|---|---|
| Approach: | 6.5km ENE of Belcoo. |
| References (1) | |||
|---|---|---|---|
| Philcox, M.E., Baily, H., Clayton, G. & Sevastopulo, G.D., 1992. Evolution of the Carboniferous Lough Allen Basin, Northwest Ireland. Special Publications of the Geological Society of London, numb. 62 In Basins on the Atlantic Seaboard: Petroleum Geology, Sedimentology and Basin Evolution., pp.203-215. | |||
| Map(s): | See 1:50,000 O.S. Sheet 17 (Lower Lough Erne). | ||
| Record type: | ESCR report | ||
| Entered by: | Doughty, P.J. | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Rahallan Townland, County Fermanagh, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=180. Accessed on 2026-11-08. |
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