When, therefore, the works of man--such as piers, harbours, and dwellings--become the spoil of the sea, the action has either been one effected by the force of the waves without any change of level of the land, or one in which land has simply subsided independently of the destructive action of the sea. In the extreme south of Sweden this action of land-subsidence is at present proceeding at a rate which has been determined by observations conducted for the past century and a half or more. The lower streets of many Swedish sea-port towns have thus been under water for many years, and even streets originally situated far above the water-level have been rendered up as prey to the sea by this mysterious sinking of land. Linnæus (as on a former occasion we remarked) in 1749 marked the exact site and position of a certain stone. In 1836 this stone was found to be nearer the water's edge by one hundred feet than when the great naturalist had observed it; the subsidence having proceeded at this rate and degree in eighty-seven years. The earliest Moravian missionaries in Greenland had frequently to shift the position of the poles to which they moored their boats, owing to the subsidence of land carrying their poles seawards, as it were, by the inflow of the sea over what was once dry land. On the coasts of Devon and Cornwall the observer may detect numerous stumps of trees--still fixed by their roots in the soil in which they grew--existing under water; the site being that of an old forest which was submerged by the sinking of the land, and which has become converted into the spoil and possession of the sea. Even the long arm of the sea--the 'loch' of the Scotch and the 'fjord' of Norway--which seen in the outline of a map, or in all its natural beauty, imparts a character of its own to the scenery of a country, exists to the eye of the geologist simply as a submerged valley, whose sides were once 'with verdure clad,' and on whose fertile slopes trees grew in luxuriant plenty. The subsidence of the land has simply permitted its place to be occupied by water, and the vessel may sail for miles over what was once a fertile valley.