The shores are so extensively indented with voes, or firths - the result partly of denudation and partly caused by glaciers - that no spot in Shetland is more than 3 m.
After conquering the Ordovices in North Wales and the island of Mona (Anglesey), during the next two years he carried his victorious arms to the Taiis (Tay; others read Tanaus, perhaps the north Tyne), and in his fourth campaign fortified the country between Clota and Bodotria (the firths of Clyde and Forth) as a protection against the attacks of the Caledonians.
Those which breed in winter or spring deposit their spawn near the coast at the mouths of estuaries, and ascend the estuaries to a considerable distance at certain times, as in the Firths of Forth and Clyde, while those which spawn in summer or autumn belong more to the open sea, e.g.
The rule of Alstahoug extended over all the neighbouring districts, including Dass's native island of Hero, and its privileges were accompanied by great perils, for it was necessary to be constantly crossing stormy firths of sea.
Excepting on the west fronts of Pomona, Hoy and Rousay, the coast-line of the islands is deeply indented, and the islands themselves are divided from each other by straits generally called sounds or firths, though off the north-east of Hoy the designation Bring Deeps is used, south of Pomona is Scapa Flow and to the south-west of Eday is found the Fall of Warness.