Staffa

The island of Staffa lies to the west of Mull, about an hour's boat ride from the better known island of Iona. Iona has a small village, sandy beach and is best known for its abbey, where St Columba established a community in 563AD. Staffa, on the other hand, is a much wilder place, and a must-see for the wandering geologist.

The geology of Staffa consists of three layers of volcanic deposits. The base is unremarkable, a black lava with airfall deposits (tuff). The middle, and most spectacular layer of lava has cooled to form columnar joints. These joints commonly form in slowly cooling lava, but Staffa's are the best I've come across, and in places are 20-30m high. The columns form perpendicular to the top surface of the lava flow; where the lava is thick and forms domes, the columns radiate outwards. The top layer of basalt is similar to the basal layer and lacks columns, but has protected the columns from erosion.

Staffa is also famous for Fingal's Cave, a large sea cave on the southern side. It was made famous by Sir Joseph Banks, and has been visited by the composer Felix Mendelssohn, Queen Victoria and many others.

We were told that in the seventeenth century, up to six families lived on Staffa, but the last left (or were blown off) by about 1800. Today the island's covered in grass and spring flowers, and the only sign of human visitation is the ruin of a nineteenth century visitors' shelter. On a fine day it was idyllic, but in a cold North Atlantic winter it must have been a bleak purgatory.