Whitfield Gill and Mill Gill

Site of Special Scientific Interest · 54.3244, -2.1059

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Also within

North Yorkshire County YORKSHIRE DALES National Park

Condition (Natural England)

Favourable (3)
UnitFeatureConditionArea (ha)Assessed
SD922926 — Favourable 6.43 2023-03-23
SD933922 — Favourable 7.53 2023-03-23
SD940913 — Favourable 4.75 2023-03-23

Climate exposure

This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.

Coastal

Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.

Habitats

Fast flowing river and stream

Geology & landscape

Geological Period: Carboniferous

Landscape processes: Coastal

Description

Description Whitfield Gill and Mill Gill consists of about four kilometres of stream sections south of Askrigg Common, lying five kilometres northeast of Hawes in North Yorkshire. Rock exposures consist of extensive cliff sections, stream floor and waterfalls. This site provides extensive exposures of the Yoredale Facies of the Askrigg Block in strata ranging from the late Asbian through almost the entire Brigantian. The sequence consists of a series of cyclothems brought about through the repeated marine inundation of river deltas which lay upon the Askrigg Block. Each cyclothem consists of seat earths, coals, clastics and limestones reflecting the flooding of the delta top, followed by the progradation of the new delta. The limestones are fossiliferous and contain a variety of corals, brachiopods and fossil algae. This fauna and flora can be used to correlate each of the cyclotherms with the fully marine successions of the surrounding strata in North Yorkshire and Cumbria. The exposures in Whitfield Gill and Mill Gill are the most extensive seen in the 'Yoredale Series' and provide a site where virtually the full succession can be studied. The site is of national importance for the study and understanding of Dinantian Lower Carboniferous stratigraphy and palaeogeography in northern England, as well as the study of sedimentary cyclicity and its causes.

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