Hewan Bank

Site of Special Scientific Interest · 55.8699, -3.1435

Open in the interactive map →

Also within

Midlothian County

Condition (NatureScot)

Favourable (1)
UnitFeatureConditionArea (ha)Assessed
F1 Quaternary of Scotland Favourable — 2018-09-24

Habitats

Fast flowing river and stream

Geology & landscape

Geological Period: Quaternary

Landscape processes: Glacial

Description

HEWAN BANK Hewan Bank Site of Special Scientific Interest (SSSI) comprises a section on the west bank of the River North Esk by Polton, southeast of Loanhead, Midlothian. The Hewan Bank is of national importance, as it represents a rare exposure of Midland Valley glacial sediments. The site is notified for its Quaternary deposits, formed during the last (Late Devensian) ice sheet glaciation. These are exposed at the top of a landslip on the west side of the river. They consist of two distinct layers of till (glacial deposits) overlain by sands and gravels (formed by glacial meltwater rivers). This sequence is characteristic of the Edinburgh and Lothian area. Earlier interpretations suggested that the tills represented two separate ice sheet stages, however they are now considered to reflect the complex and highly variable sedimentary environments associated with the melting of a single ice sheet of composite origin from separate sources in the Highlands and Southern Uplands. Hewan Bank is a key site illustrating some of the evidence used to reconstruct the glacial history of the Edinburgh and Lothian area. Furthermore, it is of notable sedimentological interest for the multiple unit depositional sequence associated with interacting ice masses from different source areas during the last glaciation.

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