Little Don Stream Section

Site of Special Scientific Interest · 53.4997, -1.6673

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South Yorkshire County

Condition (Natural England)

Favourable (1)
UnitFeatureConditionArea (ha)Assessed
SE221003 — Favourable 1.02 2010-03-30

Habitats

Fast flowing river and stream

Geology & landscape

Geological Period: Carboniferous

Description

Description The Pot Clay Coal and the Gastrioceras subcrenatum Marine Band are clearly exposed in the banks of the Little Don. The sequence yields an abundant fauna of non marine and marine bivalves and goniatites as well as a rich miospore assemblage. The G. subcrenatum Marine Band was designated as the base of the Westphalian Series more than 40 years ago. Later the Little Don was proposed as the defining stratotype for the base of Westphalian A. Thus, as the proposed stratotype for one of the major chronostratigraphical subdivisions of the Carboniferous System, this is a site of considerable international importance. In layman’s terms, the interest of this site may be expressed more simply and such a statement is provided below. This should not be taken as definitive and further information as to details of the interest can obtained from the Nature Conservancy Council. "The rocks exposed on the banks of the Little Don stream section are the formally proposed reference section for the base of one of the major units Westphalian A of the Carboniferous System, laid down about 310 million years ago. The site thus constitutes the yardstick against which all rocks of comparable age throughout the world are measured and therefore is of international importance for geology. The rocks contain abundant fossils, of both macroscopic and microscopic size and this allows easy comparison of the rocks seen here with rocks of similar age elsewhere. In addition to the marine band which marks the position of the reference section, a coal seam known as the Pot Clay Coal is also well seen here."

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