Holland On Sea Cliff

Site of Special Scientific Interest · 51.8048, 1.2060

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Also within

Essex County

Condition (Natural England)

Unfavourable Recovering (1)
UnitFeatureConditionArea (ha)Assessed
TM211166 — Unfavourable Recovering 0.09 2010-01-13

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: Quaternary

Landscape processes: Coastal, Glacial

Description

Description Cliff exposures at Holland on Sea comprise an important stratigraphic site closely related to the diversion of the Thames. The latter event, of great significance to the geomorphological evolution of the London Basin, was the result of blocking of the early Thames Valley across central Essex by the Anglian glaciation. At Holland two gravels are exposed, the site representing the type locality of both. The 'Lower Holland Gravel' is recognised as the final terrace aggradation by the Thames before its diversion, here including a small but significant contribution from the contemporary River Medway, which has been traced across eastern Essex to its confluence with the Thames in this area. The overlying 'Upper Holland Gravel' has a very different composition indicating that it is largely a Medway deposit, although with a proportion of glacial outwash material. A gravel of this type could only have been deposited while the Thames was blocked by ice and not reaching this lower part of its valley, since the eventual diversion of the Thames re routed it via London and the old Medway valley to the Clacton area, truncating the Medway in the area of the modern Thames estuary. The events represented in the Holland section are of great significance in the reconstruction of the Pleistocene history of the Thames. As they can be precisely attributed to the Anglian glaciation, they provide a fixed dating point within the terrace sequence of the eastern London Basin and a means of correlation with sequences where the Anglian is represented elsewhere in southern Britain and on the continent. The Holland cliff section therefore represents a stratigraphic site of considerable importance.

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