The face of the country exhibits a prospect of black craggy mountains and marshy plains, interspersed with some verdant spots which appear smooth and fertile. Neither tree nor shrub is to be seen, except the juniper and heath.
“Throughout the horrid wild no tree was seen,
Earth, clad in russet, scorn’d the lively green.”
This want of trees and shrubs is the more remarkable, as in different parts of these islands there are evident marks of their having been once a wooded country. In the island of Foula are often found the remains of large trees laid bare by the violence of some tempest, carrying away the strata which covered them. At present, however, no kind of wood can be made grow; and it is found extremely difficult to cultivate even the lowest and most common shrub. This decrease of vegetation has not been satisfactorily accounted for.
The nature of the soil is very different. In some places it consists of deep moss, with a sandy bottom; in others the moss is only about a foot deep over a stratum of clay. The cultivated parts consist generally of a mixture of clay and small stones. In some places there is abundance of tough clay, similar to that used in Britain in the manufacture of bricks or pottery.
No coal has hitherto been discovered in these Islands, but in several of them are found limestone, freestone, rock-crystal, corals, white spar, iron-ore, copper-ore, sulphur, fuller’s earth, and veins of variegated jasper.
Springs of fresh water are frequent in the mountains; and there are numerous lakes and streams, abounding in salmon, trout, &c.
Along the shores are a great many ancient towers, originally known by the names of Burrows or Duns; but by the inhabitants they are now called Wart or Wardhills. They were so arranged, that the whole Islands could, by signals from one to another, be apprised of approaching danger in a very short time. Sometimes they were used for state prisons. Vid. Baxter, Gloss. Antiq. Brit.
Some of these are surrounded with dry ditches, others with walls. I saw one in Unst, called Snaburg, which has both a wet and a dry ditch. One of these ditches is cut with great labour through the solid rock.