Barra Head - Geography and Geology

Geography and Geology

Berneray lies to the west of the Sea of the Hebrides and south of Mingulay across the Sound of Berneray, which has a strong tidal stream. The wedge-shaped island is 3 kilometres (1.9 mi) long and 1.3 kilometres (0.8 mi) wide. The topography lacks variety, there being no valley or bays and the few streams are very small. Most of the island consists of gneiss, although the lighthouse was constructed of rock from a small granite quarry.

The seabed to the west is a continuation of the gneiss platform with a depth of between 120 to 140 metres (395 to 460 ft). The sea floor is largely devoid of sand and there is some evidence of scouring by icebergs. This rocky platform extends south of Barra Head by at least 50 kilometres (31 mi). Due to glacial action the sea channel to the east is significantly deeper than the open ocean to the west, reaching up to 365 metres (1,198 ft).

The rocky north coast has a small landing place at Leac na Fealia to the west and a small jetty at Achduin further east. From there a track leads westward and upward across the slope of the island to the lighthouse. To the west of Achduin the land is relatively flat and low-lying, the area known as "The Aird" ending at Nisam Point which overlooks the little islands of Rubha Niosaim and Sgeir Mhor.

The south coast is dominated by high cliffs, which rise to 190 metres (623 ft) at Skate Point (Rubha Sgait) in the south west. Barra Head itself is the southern prominence located mid-way along the south coast. The highest point of the island is Sotan, a Marilyn whose summit lies above high cliffs between Barra Head and Skate Point. This eminence is easily reached from the track that leads from Achduin to the lighthouse that passes just to the north of the summit, which is only 3 metres (9.8 ft) from the cliff edge. The skerry of Bird Rock guards the coast far below. The lighthouse is located near the prominence of Sròn an Duin, just east of Skate Point and above the narrow chasm of Sloc na Bèiste (ravine of the monster).

Visiting in 1868 H. J. Elwes wrote:

It was the grandest sight I ever experienced, to look out of the lighthouse on a very stormy day, and see oneself hanging, as it were, over the ocean, surrounded on three sides by a fearful chasm in which the air was so thickly crowded with birds as to produce the appearance of a heavy snowstorm, whilst the cries of these myriads, mingled with the roar of the ocean and the howling of the tremendous gusts of wind coming up from below as if forced through a blast pipe, made it almost impossible to hear a person speak.