Excursion 4: The Sgurr of Eigg (Route map 1)

Climbing the Sgurr is in every way the culmination of a visit to Eigg, and given reasonable weather is not to be missed. The route described takes visitors to the top by the easiest way. Those seriously interested in the geology will wish to follow the more strenuous continuation.

The approach to the Sgurr from Galmisdale

From Glebe Barn take the road to Galmisdale House via Sandavore (yellow dots). A path leads southwards and eventually turns westwards towards Grulin. Alternatively, coming from the pier take the track directly uphill through the woods, past the entrance to the Lodge gardens and the community hall, and on to the track behind Galmisdale House.

Just to the west of Galmisdale House, a cairn [NM 4739 8405] marks the start of a rough path (red dots) that leads up a small valley towards the ‘nose’ of the Sgurr. All this hillside shows excellent development of ‘trap topography’: natural terracing caused by the differential erosion of the resistant centres and crumbling tops of successive lava flows (page 18). The centres of flows, forming bluffs on the hillside, are often columnar. As you traverse the trap terraces, the Sgurr towers ever more impressively above you. At this end of the Sgurr ridge, only half of the former valley into which the pitchstone flowed is preserved; its southern half has been eroded away. The northern side of the valley can be seen ahead, the basalt terracing apparently truncated by the pitchstone. The pitchstone is strikingly columnar: the upper part, as seen from this angle, has vertical columns, but in the lowest part the columns incline steeply to the north, “as if losing footing under the superincumbent weight” (Miller). They are thus perpendicular to the former valley side, against which the pitchstone cooled.

From here, below The Nose, follow a level but often muddy path to the north of the pitchstone ridge. In a few hundred metres the first wide gully [NM 4587 8486] encountered leads without much difficulty to a col. The view northwards and westwards reveals the extent of the pitchstone outcrop. From a distance the Sgurr pitchstone outcrop can easily be mistaken for a simple south-east to north-west ridge, but in reality its outcrop extends to the hills of Corra-bheinn and Beinn Tighe. The contrast between the grey-weathering pitchstone and the brown basalt shows that the pitchstone fills valleys that were eroded in the basalts in Palaeogene times (page 26).

From the col, the easiest way to the summit, a few hundred metres to the east, is to follow the red dots and take a rough path [NM 4587 8477] that climbs steeply to a small lochan. The path eastwards from here is undulating, but with a steep drop to the right in places. On the way, note the extremely irregular disposition of the columnar joints, which contrasts with their regularity nearer the base. After the first part of the climb look back: the mountains of Rum seen over the pitchstone columns form a truly impressive vista (Figure 4).

The view from the Sgurr summit itself [NM 4637 8470] is justly famous. Miller described it in 1844:

“It was now evening, and rarely have I witnessed a finer. The sun had declined half-way adown the western sky, and for many yards the shadow of the gigantic Scuir lay dark beneath us along the descending slope. All the rest of the island, spread out at our feet as in a map, was basking in yellow sunshine......... The sea, spangled in the wake of the sun with quick glancing light, stretched out its blue plain around us; and we could see included in the wide prospect, on the one hand … the hills of Morvern and Kintail, with the many intervening lochs and bold jutting headlands that give variety to the mainland; and on the other, the variously-complexioned Hebrides, from the Isle of Skye to Uist and Barra, and from Uist and Barra to Tiree and Mull. The contiguous Small Isles, Muck and Rum, lay moored immediately beside us, like vessels that in some secure roadstead drop anchor within hail of each other. I could willingly have lingered on top of the Scuir until after sunset...”

People with a keen geological interest will wish to examine the exposures on the south side of the ridge by following the extension described below. Others may think the conquest of the Sgurr enough for one day, and return by the same route to Galmisdale House.

Excursion 4 extension: beneath the Sgurr pitchstone

The critical locality is the Recess, on the south side of the Sgurr ridge [NM 4602 8461]. Assuming one has climbed the Sgurr and does not want to lose height, the quickest route is to return to the col and descend the steep south side of it. Bear left, keeping the pitchstone on your left, until the Recess is reached.

It is possible to visit the Recess before the summit, either by climbing directly from the Grulin road, or from The Nose. From The Nose, follow the base of the pitchstone down the steep southern slope as closely as you can, avoiding scree on the one hand and deep heather on the other. Small overhangs indicate the position of the base of the pitchstone. Where the dip of the base flattens somewhat, contour along the hillside. Below you, on a very steep slope, are exposures of an impressively coarse conglomerate. It contains rounded boulders of basalt, up to nearly a metre in diameter, and much smaller pebbles of Torridonian sandstone. The boulders are clearly water- rounded, and must have accumulated near the bottom of the pre-pitchstone valley.

The Recess

A series of recesses, which serve as natural sheep-shelters, are found between the basalts beneath and the pitchstone above. The largest of these is the classic locality where the Eigg Pine was found (page 28), and where critical evidence for the origin of the pitchstone (page 26) can best be seen. The floor of the Recess (Figure 38) is formed of a conglomerate, less well sorted than that to the east, with pebbles of basalt and some conspicuous large boulders of Torridonian sandstone.

Above the conglomerate, and exposed in the back wall of the Recess, is a remarkable breccia, or fragmental rock, consisting of fragments of fresh black pitchstone enclosed in a soft yellow matrix of decomposed pitchstone. Above that, fresh columnar pitchstone forms the roof. According to Geikie, and present views, the conglomerates were deposited on the floor of the old valley. The brecciated pitchstone is described as a peperite by Brown and Bell (page 27), and probably resulted from pyroclastic flows moving across and mixing with wet sediment. Wood has been found in both the conglomerate and the decomposed pitchstone breccia, in which the main log of the Eigg Pine was found (page 28). On Harker’s reading of the pitchstone as a sill this is, to put it mildly, hard to explain. If the tree was overwhelmed by a pyroclastic flow, however, it is easily explicable.

Descend, with care over a steep and rough hillside, from the Recess to the Grulin track, which is clearly visible below, and return along it to Galmisdale.

If you have come to the Recess from the Grulin road, or from The Nose, before climbing the Sgurr itself, continue west beneath the pitchstone until you reach the first gully: this leads to the col described previously. It is steep but not difficult. Make the ascent from the col. The northern route may then be used for the descent, back to The Nose and to Galmisdale.

Figures

(Figure 36) The Sgurr with Galmisdale House in the foreground.

(Figure 37) Map of the pitchstone outcrop, showing the locations of valleys eroded in the older basalt lava flows. By permission IPR/25-11C— British Geological Survey.

(Figure 38) Sketch of deposits at the Recess beneath the Sgurr.

(Figure 39) Conglomerate beneath the Sgurr.

(Figure 40) Breccia in the main Recess below the Sgurr.