Melby

Site of Special Scientific Interest · 60.3014, -1.6814

Open in the interactive map →

Also within

Shetland County

Condition (NatureScot)

Favourable (2)
UnitFeatureConditionArea (ha)Assessed
F1 Non-marine Devonian Favourable — 2016-04-19
F2 Silurian - Devonian Chordata Favourable — 2014-04-23

Habitats

Fast flowing river and stream

Geology & landscape

Geological Period: Devonian, Silurian

Landscape processes: Fluvial, Volcanic / Igneous

Description

Melby Melby Site of Special Scientific Interest (SSSI) is located in Sandness, in the north-west of Shetland West Mainland. It comprises four sections of sea cliffs along the coastline between Lang Rigg and Matta Taing, and is notified for its Middle Devonian sedimentary rock sequence and the presence of two fossil fish beds of paleontological interest. Non-marine Devonian The site contains spectacular exposures of rocks belonging to the Middle Devonian Melby Formation. These demonstrate the varying depositional environments during lake transgression (expansion) and regression (shrinking) in the northernmost part of the Orcadian Basin. Fine-grained, thinly bedded or laminated lake sediments with carbonate (and locally sulphide) nodules are interbedded within a dominantly fluvial sequence, both containing volcanic detritus. The lake sediments include the Lower and Upper Melby Fish Beds which are of palaeontological importance. The river-deposited fluvial sediments are mainly thick cross-bedded sandstones. Dominant current-flow directions change, with flow from the west in the lower part of the sequence, below the Upper Melby Fish Bed, changing to flow from the east, and a new source of volcanic detritus, above the Upper Melby Fish Bed. This is of palaeogeographical significance. Silurian – Devonian Chordata The site contains the most northerly confirmed outcrops of Middle Devonian age (around 390 million years old) fish beds that are also exposed at Achanarras in Caithness. This is the best exposure of this fish bed horizon in Shetland. Fish fossils in the Lower and Upper Melby Fish Beds are mainly found in carbonate (and locally sulphide) nodules, which indicates a lake margin environment. The site yields a typical, although restricted, Achanarras horizon fauna and it is an outstanding locality for its bearing on paleo-ecological studies. Species recorded include: Cheiracanthus sp., Coccosteus cuspidatus, Coccosteus sp., Dipterus valenciennesi, Homosteus milleri, Mesacanthus sp. and Pterichthyodes milleri.

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