Glen Feshie
Geological Conservation Review site | GCR #3049 | Quaternary Geology | Quaternary of Scotland
Scotland's geosites are chosen because of their local, national or international importance. Take only photos, leave only footprints: avoid causing any damage to this site. You can walk almost anywhere in Scotland without the need to ask permission or keep to paths, but you have a responsibility to care for your own safety, to respect people's privacy and peace of mind and to cause no damage.
This site is a Site of Special Scientific Interest (SSSI). It is an offence to intentionally or recklessly damage the protected natural features of a SSSI, and this includes unauthorised sample collection.
The right of access does not extend to quarries, building sites or any land where public access is prohibited, or to the collection of geological samples.
Summary
The landforms and deposits of upper Glen Feshie include alluvial fans, outwash and river terraces, palaeochannels, kames and kettle holes. This assemblage of features provides an outstanding record of valley-floor and valley-slope development during the Late Glacial and Holocene.
Glen Feshie is a site of highest importance for Quaternary glacial and post-glacial features. A series of coalescing debris cones at Creag na Caillich were formed by post-glacial slope processes. The Allt Lorgaidh fan nearby is important for studies of alluvial fan development and for dating river terrace sequences, using buried soils present in this part of Glen Feshie. Further downstream on the northern side of the river, the Allt Garbhlach fan and associated outwash plains (palaeosandur) were formed during the later stages of the Devensian ice-sheet deglaciation around 13,000BP.
In the reach between Allt Garbhlach and Auchlean there is an excellent example of a well-preserved river terrace system dating from the late Devensian to the late Holocene. In the lower parts of the glen, river terraces are clearly visible in the valley floor near Ballintean. The River Feshie flows through an extensive post-glacial alluvial fan as it approaches the confluence with the River Spey, with a course that is frequently modified by channel switching caused by highly variable discharges.
Site information
Access
The upper valley is best accessed from the private road to the west of Glen Feshie as far as Ruigh Fionntaig (NN 8435 9175). The public car park near Auchlean (NN 8503 9851) gives access to the east of the glen by road, track and public footpath. Allt Fhearnagan is crossed at a ford, so would not be accessible at times of high river discharge. A footpath from Ballintean to Feshiebridge leads across the lower river terrace. The alluvial fan north of Feshieside to the confluence of the Feshie and the Spey is not easily accessible.
Safety notes
Access to the upper stretches of Glen Feshie is by way of footpaths and tracks using fords and bridges across the tributaries to the River Feshie, not all of which are passable safely at times of high river discharge.
Related geosites
Alison Tymon
Sept. 19, 2023
From a footpath near Kincraig, the River Spey can be seen at the base of the wooded cliff. Beyond lies the late-glacial alluvial fan built out by the River Feshie, now largely stabilised by woodland. The Feshie channels on the alluvial fan change position frequently during flood times and the history of this feature is best traced on old maps and using aerial photography.
Alison Tymon
Sept. 19, 2023
The lowest river terrace in the Feshie valley is seen here, eroded on the right by a recent river channel. The footpath follows the line of a long-abandoned river channel which continues to meander into the distance beyond this view.
Alison Tymon
Sept. 20, 2023
A view from close to the Auchlean car park shows the three post-glacial river terraces in the valley. The fenced lane runs along the highest terrace which slopes steeply down to the middle terrace, dated at 3,600 BP. The meadow near the river is the lowest terrace and on all the terraces, fossil river channel features can be identified.
Alison Tymon
Sept. 20, 2023
The heather and bilberry-covered foreground covers the late-glacial outwash plain to the north of the Allt Garbhlach fan. Subtle changes of relief on the terrace show that river channels flowed downstream from south to north about 10,000 BP. Glacial till mantles the lower slopes of the hillsides beyond.
Alison Tymon
Sept. 20, 2023
In the foreground, amongst heather and bilberry, is a small kettle hole. A kettle hole is a depression of damp ground denoting where a block of ice left on the outwash plain (palaeosandur) melted slowly as temperatures rose at the end of the last ice event. Damp-loving vegetation, such as sedges and cotton grass, grow in these areas and help to identify these features.
Alison Tymon
June 7, 2024
A large, elongated kettle hole, viewed from the north side, can be found close to the path up the valley lying behind a bank and surrounded by forestry plantations.
Alison Tymon
Sept. 20, 2023
The view down Glen Feshie shows the lowest river terrace, at 1.5 m above present river level, into which the River Feshie is cutting a single channel. Subtle changes in level show the curves of abandoned Holocene river channels. The terrace is edged by the steep wooded bank up to the middle terrace at 3m above river level.
Alison Tymon
Sept. 20, 2023
The River Feshie is cutting into river terraces at the base of the Allt Garbhlach fan, as seen in the coarse boulders and clays in the eroded river cliff. The most recent river terrace, to the left of the present river channel, dates from about 1000 BP and further accumulations of river cobbles are gradually being stabilised by vegetation.
Alison Tymon
Sept. 20, 2023
The hummocky features on the distant hillside mark kames or kame terraces on the Allt Garbhlach alluvial fan, which probably formed during the melting of small glaciers on the Cairngorm hills to the east at about 13,000 BP. In the foreground are post-glacial river terraces.
Alison Tymon
Sept. 22, 2023
The Allt Lorgaidh fan has several units which relate to the raised terrace levels seen further downstream in the Feshie valley. A buried podsol, which gives a date of about 3,600 BP, has been located in the bed of this burn.
Alison Tymon
Sept. 22, 2023
The view up the valley of the Allt Lorgaidh shows both active and stabilised scree slopes, with glacial hummocky ground on the valley sides. In the foreground is the gently convex Allt Lorgaidh alluvial fan.
Alison Tymon
Sept. 20, 2023
Post-glacial weathering of the Moine schists of Creag na Caillich has formed three coalescing debris cones. The cones continue to contribute material to the River Feshie as they are eroded at times of high river discharge.