Conagher

Also within

Fermanagh County

Habitats

Fast flowing river and stream

Geology & landscape

Geological Period: Carboniferous

Description

Conagher Upper Palaeozoic palaeontology Conagher is one of only three sites, of any age, in Northern Ireland which has yielded well-preserved and articulated fish remains and one of only a handful of such sites in Ireland as a whole. First discovered in 1963, the fish fauna so far recovered is of one species only. However the abundance of material and the presence of terrestrial plant remains suggest the site will reward further investigation. The locality is exposed along the banks of the Sillees River and one of its tributaries. The host rocks are a series of rather soft, sometimes blocky, grey mudstones alternating with harder, dark-grey, laminated limestones. The succession lies within the lower part of the Meenymore Formation, part of the Carboniferous Leitrim Group and dates from some 340 million years ago. Strata some 6 metres below the fish-bearing beds have yielded specimens of the goniatite Beyrichoceras microllotum, indicating a B2 Zone age and a position in the late Asbian. All fish material recovered to date can be assigned to the palaeoniscid fish Elonichthys serratu. The environmental conditions at the time of deposition appear to have been a marginal marine setting with evaporitic periods and occasional marine incursions. The presence of goniatites only six metres below the fish-bearing horizons indicates that fully marine conditions prevailed across the area only shortly before deposition of the fish-bearing material. An unequivocally marine fauna is however absent, the fauna is instead very limited in terms of species diversity. The only fossils recovered other than the numerous fish remains are limited to possible fern and small plant stem remains. This suggests proximity to some landmass, while the monospecific fish fauna suggests quasi-marine, probably brackish, conditions. The well-laminated nature of the rock indicates a virtual absence of benthic infauna or epifauna, resulting in an absence of bioturbation, which, together with their slightly bituminous nature, suggests benthic anoxia on at least a local scale. This anoxia and the lack of benthos arising from it has been a major factor contributing to the exceptional preservation of the fish at this site. The lack of benthos arising from it has been a major factor contributing to the exceptional preservation of the fish at this site. https://www.daera-ni.gov.uk/publications/conagher-assi

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