Quinag

Ascent — around 800 metres

Difficulty — strenuous mountain walk

Duration — about 6 hours circular walk

Start — grid reference [NC 233 274]

The three main peaks of Quinag dominate the landscape to the north of Loch Assynt. The climb to Sàil Gharbh, the highest summit, takes you across Torridonian Sandstone and Cambrian Quartzite, and explores the evidence left behind by the glaciers that shaped this mountain. The walk follows paths for most of its route, but much of it is on high, broad ridges; good boots and warm clothing are essential, and most reasonably fit walkers should be able to complete the route.

Three kilometres north of Skiag Bridge, park at the car park near the high point of the A894. Cross the road, and follow the stalkers’ path that climbs steadily westward into the corrie between Spidean Còinich and Sàil Gharbh. On either side of the path are slabs of white Cambrian Quartzite. Some of these slabs are covered in roughly parallel, north – south scratches — these are glacial striae, which provide evidence that a glacier moved in a northerly direction over these rocks. That glacier occupied the main valley about 20 000 years ago, whereas the corrie before you was occupied by a smaller glacier around 11 000 years ago.

The path levels off for about 500 metres, and crosses a peaty flat covered in quartzite boulders.

Higher up, you leave behind the grey-white gently sloping quartzite slabs and pass on to horizontally layered red-brown Torridonian Sandstone [1] [NC 22298 27969]. You have crossed an unconformity and are now walking on rocks that are twice as old as the quartzite. This unconformity represents a time gap of more than 400 million years, during which time the Torridonian Sandstone was tilted and then eroded, before being covered by the Cambrian Quartzite.

The path ascends a steep peaty slope, passing a large vertical sandstone boulder resembling a prehistoric monolith. This boulder was deposited by a glacier near the end of the ice age and is not the work of man! Higher in the corrie, near the lochan, the ground is strewn with quartzite boulders — a further sign that a small glacier once occupied this corrie.

Climb to the head of the corrie and onto the col (the Bealach a’ Chornaidh), a good place to rest and look out towards the Atlantic. Canisp, Suilven, Stac Pollaidh and Point of Stoer are all visible on a clear day. From the col there is a stiff climb up the path on the north side of the bealach, weaving through rocky crags. These crags are composed of purplish brown Torridonian Sandstone that shows excellent cross- bedding. In many places you can see pebbly layers in the sandstones, with rounded lumps of red and white quartz that still look as fresh as when they were laid down on a river bed almost 1000 million years ago.

Above the crags, the path levels out and you reach the 745 metre peak from which the ridges of Quinag radiate, a splendid viewpoint [2] [NC 20093 28948]. To the west lies the characteristic cnoc-and-lochan landscape of the Lewisian Gneiss, cleared by the scouring action of glaciers. Beneath you is the west wall of Quinag, a cliff of Torridonian Sandstone dropping steeply to Gleann Leireag below. This cliff marks the line of a fault — a fracture in the Earth’s crust that has been exploited by the erosive power of water and ice over millions of years to form the glen. To the south, you can clearly see the layer of pale grey Cambrian Quartzite that caps Spidean Còinich, resting on top of the red-brown layered Torridonian Sandstone. The unconformity between these two rock types slopes down towards the east, so that quartzite is seen much lower down on the east ridge of Spidean Còinich than it is at the summit.

From the 745 metre peak, walk east down on to a col covered in a pavement of rounded flat slabs of Torridonian Sandstone. The slabs are mostly in their original positions, and are surrounded by a carpet of sand and fine gravel. This landscape is the product of wind erosion over thousands of years.

Continue along the gently rising ridge of Sàil Gharbh, Quinag’s highest peak [3] [NC 20922 29204]. The lower part of the ridge has exposures of cross- bedded Torridonian Sandstone, but the peak is capped by grey Cambrian Quartzite, which would once have been continuous with that on Spidean Còinich.

The summit is covered in large angular quartzite boulders; this is known as a blockfield. Exposure of the rocks to repeated freeze-thaw cycles over thousands of winters has caused the bedrock to break into small blocks. The presence of the blockfield tells us that the Sàil Gharbh ridge has been exposed to the weather for a long time and probably remained ice-free during the last main glaciation, about 20 000 years ago. However, the lower slopes would have been covered by a thick sheet of ice, slowly flowing westwards, which would have removed loose rock.

After admiring the views from Sàil Gharbh, retrace your steps to the 745 metre peak and down to the Bealach a’ Chornaidh. From here, the easiest way back is by the stalkers’ path in the corrie, but those who still have fresh legs may choose to return over Spidean Còinich. This shapely square-topped peak is easily climbed from the bealach. The path climbs steeply, levels off, and then climbs again to the summit, which is covered in a quartzite blockfield. As with Sàil Gharbh, this summit was free of ice during the last glaciation.

The descent is by the south-eastern ridge [4] [NC 21521 27140]. The upper part of this ridge is covered in angular quartzite blocks, which can be quite awkward underfoot. Lower down, smooth sloping surfaces of white Pipe Rock are exposed; look closely and you will see the rounded marks on the surface that were formed by burrowing worms. These rock slabs represent ancient beach surfaces. They were laid down as sheets of white sand about 500 million years ago, and have since hardened to form quartzite and then been tilted by Earth movements. Continue down the ridge to rejoin the path just before the road.

Figures

(Figure 74) Quinag. Painting of walk by Elizabeth Pickett.

(Figure 75) Ardvreck Castle and Quinag from Loch Assynt.

(Figure 76) Exposure of the unconformity a short distance from the path in the eastern corrie of Quinag.

(Figure 77) Cross-bedded sandstone above Lochan Bealach Cornaidh.

(Figure 78) View of Spidean Còinich showing the Cambrian unconformity.

(Figure 79) Mosaic of Torridonian Sandstone slabs on the col west of Sàil Gharbh.

(Figure 80) Cross-bedded Torridonian Sandstone on the Sàil Gharbh ridge.

(Figure 81) Quartzite blockfield on the summit of Sàil Gharbh.

(Figure 82) Spidean Còinich, with its grey quartzite summit capping a ridge of Torridonian Sandstone.