Little River

Site of Special Scientific Interest · 54.5972, -6.8739

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Also within

Tyrone County

Habitats

Fast flowing river and stream

Geology & landscape

Mining / Industrial: Quarry · Geological Period: Ordovician, Silurian · Rock Type: Slate

Description

Little River Ordovician stratigraphy Around Slate Quarry Bridge, the Little River, and its tributary the Tirnaskea Stream, expose fossiliferous Upper Ordovician and Lower Silurian age rocks, some 430-440 million years old M.y.. Within this relatively small area the complexity of the Pomeroy Lower Palaeozoic inlier is uniquely exhibited. The site has a significant palaeontological history with pioneering work by Major-General Portlock in 1843, since when it has been intensively stUdied. A number of exposures within the site constitute the type localities for over 60 fossil species including 2 important genotype species. A type locality is the site from which the species were first described. The site is particularly rich in trilobites, gastropods and brachiopods. The site also holds an uninterrupted series of sediments laid down during the Ordovician-Silurian transition, some 430 M.y. Rock types and the contained fossil evidence indicate that the rocks were deposited in a relatively deep water, outer continental platformal setting. There is strong evidence for regular downslope mass movement of sediment, which carried with it faunas from more upslope environments. https://www.daera-ni.gov.uk/publications/little-river-assi

Plant communities

A9 — Fast flowing river and stream, Marginal and inundation, Pond ditch and canal, Sluggish river and stream

Potamogeton natans community

Schoenoplectus lacustris, Juncus bulbosus, Sparganium angustifolium, Sparganium erectum, Sparganium minimum, Alisma plantago-aquatica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Elodea canadensis, Lemna minor, Lemna trisulca, Nymphaea alba, Callitriche platycarpa, Callitriche stagnalis, Littorella uniflora, Potamogeton natans, Ranunculus trichophyllus, Glyceria fluitans, Chara subspinosa

A14 — Fast flowing river and stream

Myriophyllum alterniflorum community

Isolepis fluitans, Juncus bulbosus, Fontinalis antipyretica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Lemna minor, Callitriche stagnalis, Littorella uniflora, Potamogeton filiformis, Potamogeton gramineus, Potamogeton natans, Ranunculus peltatus, Chara spp., Nitella hyalina

A17 — Chalk river and stream, Fast flowing river and stream

Ranunculus penicillatus ssp. pseudofluitans community

Berula erecta, Nasturtium officinale, Elodea canadensis, Lemna minor, Callitriche stagnalis, Veronica beccabunga, Polygonum amphibium, Polygonum hydropiper, Potamogeton crispus, Potamogeton pectinatus, Ranunculus penicillatus ssp. pseudofluitans

A18 — Fast flowing river and stream

Ranunculus fluitans community

Fontinalis antipyretica, Fontinalis squamosa var. curnowii, Myriophyllum alterniflorum, Myriophyllum spicatum, Elodea canadensis, Mentha aquatica, Lemna gibba, Lemna minor, Potamogeton perfoliatus, Ranunculus fluitans, Glyceria fluitans, Phalaris arundinacea