ESCR - Introduction to the Palaeontological sites of Northern Ireland

Earth Science Conservation Review

Summary Full report
Introduction to the Palaeontological sites of Northern Ireland	Antrim, Armagh, Down, Fermanagh, Londonderry, Tyro

Site number:	109
Locality Type:	Various
Grid Reference:
Google maps:	,
County:	Antrim, Armagh, Down, Fermanagh, Londonderry, Tyro
Period:	Quaternary, Tertiary, Cretaceous, Jurassic, Triassic, Permian, Carboniferous, Devonian, Silurian, Ordovician, Precambrian

Site Description
Introduction:
The geology of Northern Ireland records a fascinating history of events extending over more than 800 million years. The varied geology gives rise to often striking scenery and some of the most spectacular geological sites anywhere in Britain or Ireland. Indeed, the Giant's Causeway represents the only geological World Heritage Site anywhere in Britain or Ireland. However, this wealth of geological features in the province is not reflected in a similar richness of palaeontologically important sites. Although many of the marine sequences in Northern Ireland do contain fossils which are important for any palaeoenvironmental or biostratigraphic interpretation, the contained biota often is unremarkable by comparison with many palaeontologically important sites elsewhere in the UK. Nonetheless, some important sites do exist in areas that have not otherwise been designated as Areas of Special Scientific Interest (ASSIs). The geological succession in Northern Ireland spans more than 800 million years yet is far from complete. Even those parts of the succession that are present are not always fossil bearing. Significant parts of the geological column are represented by metamorphic rocks too old and deformed to yield any recognisable fossils, by extrusive or intrusive igneous rocks, or by non-marine sediments in which fossils are rare or absent. In fact richly fossiliferous rocks form only a very small proportion of the total in Northern Ireland. The palaeontological significance of the various parts of the geological succession in Northern Ireland is summarised below.
Description:
PRECAMBRIAN (DALRADIAN) Schists and marbles of late Proterozoic age outcrop over a large area of the Co. Derry lowlands as well as in the Sperrin Hills of Co. Tyrone and in north Co. Antrim east of Ballycastle. They have experienced substantial deformation and, furthermore, predate the first appearance of macrofossils. ORDOVICIAN AND SILURIAN A substantial thickness of turbiditic greywackes and mudstones, with minor volcanics, outcrop in a broad band extending southwestwards from the coast of Co. Down through Armagh and into the Republic. A second important outcrop, dominated by volcanics, is present in Co. Tyrone and extends into west Co. Antrim. Fossils in the greywacke-mudstone successions are common only locally and are dominated by assemblages of graptolites and pelagic trilobites. These are invaluable biostratigraphically but their generally poor preservation otherwise restricts their value. A much more diverse assemblage is present in the shallower water sandstones of the Bardahessiagh Formation in the Desertcreat Group, of late Ordovician, Caradoc, age. DEVONIAN Macropalaeontologically the Devonian strata of Northern Ireland are barren. Sandstones, conglomerates and some volcanics outcrop in the Fintona Block of Co. Tyrone but are poorly exposed. On the north Antrim coast in the Cushendun-Cushendall area Devonian volcaniclastics and cobble conglomerates are superbly exposed but neither have yielded any macrobiota. CARBONIFEROUS Marine Carboniferous rocks are abundant and widespread in the province and often are highly fossiliferous. Generally the fauna is unremarkable although certain localities deserve special mention for their palaeontological importance. Some, such as Cashel Quarry, Co. Fermanagh, have been incorporated into the stratigraphic ASSI block and have been described by Mitchell (1995). However, a number of sites that were not included in that report clearly have palaeontological significance that warrants separate ASSI status. Five Carboniferous sites are proposed as ASSIs on palaeontological grounds. i) Carrick Lough and Sillees River, Derrygonnelly, Co. Fermanagh - exposures of Carboniferous Limestone have yielded an exceptionally diverse silicified fauna, dominated by bryozoa and brachiopods, described in a series of major monographic publications. ii) Mullynaskeagh Clay Pit, Derrygonnelly, Co. Fermanagh - this site exposes the thickest development of the Sheena Shale, a highly fossiliferous unit within the Leitrim Group of the Carboniferous Limestone. It has yielded a particularly abundant and diverse assemblage of cephalopod molluscs. iii) Sillees River, Glennasheevar, Co. Fermanagh - a small site, within the Meenymore Formation of the Carboniferous Limestone, exposes laminated and bituminous micrites which have yielded exceptionally well preserved fish. iv) Moyola River - shales and sandstones in the early Carboniferous Altagoan Formation along a short stretch of the Moyola River near Maghera have yielded abundant fish debris. The site is thought to be one of Portlock's (1843) original fossil fish localities from which material described by Agassiz (1833-44) was obtained. v) Ballycastle - The exposure at Portnaloub is the finest exposure of early Carboniferous lacustrine oil shale in Northern Ireland and has yielded complete fish preserved in three dimensions. At Faragandoo a sequence of tuffs and mudstones includes several palaeosols. In situ lycopod stumps have yielded a fauna of terrestrial arthropods. PERMIAN The Magnesian Limestone outcrop near Grange, in Co. Tyrone, represents the most westerly occurrence of this late Permian marine carbonate in Europe. It is much thicker and more richly fossiliferous here than further to the east, at Cultra. Only one unfossiliferous exposure of this unit currently exists in the Grange area although it is clear that Magnesian Limestone outcrops at very shallow depth. TRIASSIC The Triassic succession in Northern Ireland, as elsewhere in Britain, is dominated by the red beds of the non-marine Sherwood Sandstone and Mercia Mudstone groups, capped by the relatively thin, quasi-marine, Penarth Group. The red beds are largely unfossiliferous although the Sherwood Sandstone Group has yielded occasional reptile footprints from the quarries on Scrabo Hill, Co. Down (Ashley 1946) and palaeoniscid fish were recovered in some abundance from one horizon in a now infilled quarry at Rhone Hill, Co. Tyrone. The Penarth Group is well exposed on the foreshore at Larne, Co. Antrim, and intermittently elsewhere. It yields a typical Penarth Group restricted fauna of molluscs and fragmentary vertebrates. JURASSIC Only the lowermost part of the Jurassic succession is preserved in Northern Ireland. In most areas only the Hettangian and lower part of the Sinemurian are preserved beneath the Cretaceous unconformity but in north-west Antrim strata as high as the Ibex Zone of the Lower Pliensbachian are recorded in the Port More Borehole while there are earlier records of horizons as high as the Davoei Zone (Wilson and Manning 1978). Evidence for the former existence in Northern Ireland of horizons as high as the Upper Pliensbachian and Toarcian comes from derived fossils in the Cretaceous basal conglomerate at Murlough Bay, which accordingly is proposed as an ASSI. The Cretaceous basal conglomerate exposed in Tircrevan Burn also is proposed as a palaeontological ASSI on account of the vertebrate remains, thought to be derived from the underlying Liassic sediments, incorporated within it. In general the Lower Lias is rather poorly exposed along the coast, being often obscured by Cretaceous and Tertiary material slumped down from above. The most important Lower Jurassic site, in palaeontological terms, is that at Minnis North where an active mudflow uncovers material from most of the Hettangian Stage. This site has yielded an unusually rich fauna and accordingly is proposed as a palaeontological ASSI. CRETACEOUS Only late Cretaceous sediments are preserved in Northern Ireland, with all but an impersistant basal unit being of post-Cenomanian age. The youngest strata are assigned to the Lower Maastrichtian. Both the Hibernian Greensands Formation and the Ulster White Limestone Formation contain typical late Cretaceous faunas and locally may be highly fossiliferous. Exposures of the Cretaceous basal conglomerate at two sites, Murlough Bay and Tircrevan Burn, are proposed as ASSIs, though largely on account of their derived Lower Jurassic faunas. The only other Cretaceous site proposed as an ASSI specifically for its palaeontological significance is the Ballycastle Pellet Chalk, whose unusual lithology has allowed a diverse calcareous microfauna to be extracted and described. TERTIARY The Tertiary succession in Northern Ireland is dominated by igneous, predominantly basaltic, extrusives of Palaeocene age. The overlying lacustrine Lough Neagh Clays are Oligocene in age and include substantial thicknesses of lignite. Plant macrofossils, particularly large masses of silicified wood, have been found at a number of localities around Lough Neagh. Within the Antrim Lava Group succession a major weathering horizon, the Interbasaltic Formation, locally has yielded significant plant assemblages. The most important of these was obtained from excavations associated with the railway cutting at Ballypalady, which is proposed here as an ASSI. PLEISTOCENE AND HOLOCENE Extensive Pleistocene and Holocene deposits, in the form of glacial till, sands, gravels, lacustrine muds and peat, blanket much of the solid geology of Northern Ireland. These deposits, as well as fissure and cave deposits, have yielded important fossil material, particularly of vertebrates. No sites are included within the scope of this report.
Notes:
For site specific information and references on the Palaeontology of Northern Ireland see Key Site 110 - Ballycastle Pellet Chalk, Key Site 111 - Ballypalady Plant Bed, Key Site 112 - Carrick Lough, Bunnahone Lough and the Sillees River, Key Site 113 - Faragandoo, Key Site 114 - Minnis North Mudflow, Key Site 115 - Moyola River, Key Site 116 - Mullynaskeagh Clay Pit, Key Site 117 - Murlough Bay, Key Site 118 - Portnaloub, Key Site 119 - Sillees River, Glenasheevar, Key Site 120 - Tircrevan Burn (palaeontology), and Key Site 121 - Tullyconnell.

Keywords

References (4)
Agassiz, L., 1833-1844. Recherches sur les poissons fossiles vol. 1-5, pp.1420, plates 369, Neuchatel.
Ashley, H., 1946. Cheirotherium footprint found at Scrabo Hill, County Down. Irish Naturalists Journal, vol. 8, pp.332.
Portlock, J.E., 1843. Report on the Geology of the County of Londonderry and of parts of Tyrone and Fermanagh. HMSO, Dublin.
Wilson, H.E. & Manning, P.I., 1978. Geology of the Causeway coast. Memoir for one-inch geological sheet 7. Memoirs of the Geological Survey Northern Ireland, HMSO, Belfast.

Record type:	ESCR report	Recorded by:	Michael J. Simms, Department of Geology, Ulster Mu
Entered by:	E M Porter

Enlander, I., Dempster, M. & Doughty, P., 2026. Introduction to the Palaeontological sites of Northern Ireland, County Antrim, Armagh, Down, Fermanagh, Londonderry, Tyro, site details. [In] Earth Science Conservation Review.
https://www.habitas.org.uk/escr/site.php?item=109. Accessed on 2026-11-06.