Beaches

Beaches, RAISED. Geology teaches that the frame of the land is liable to risings and depressions, even in the present age. Several districts in different parts of the world have been raised, in consequence of earthquakes, within the memory of the present generation; and there is evidence to show that the coast of Siberia east of the Lena, Spitzbergen, Nova Zembla, and the Scandinavian Peninsula (with the exception of Scania, in the extreme south), have been recently elevated. These facts prepare us to learn that, around the British Islands, and in other parts of the earth, there are tracts of ground at various elevations above the present sea-level which have evidently been sea-beaches at a former time. The evidences consist of, first, the levelness of the ground in the general direction of the present shores over considerable spaces; second, the alternating beds of sand and gravel, such as we see composing the present beach; and, third, the presence of marine littoral shells. There are also what may be called terraces of erosion—indentations made in a rocky coast by the lip of the sea in ancient times—usually consisting of a flat platform presenting patches of gravel, and of a backing wall or sea-cliff, the latter sometimes penetrated with deep caves. In Scotland there are several well-marked raised beaches, at 100, 75-80, 45-50, 25-30 feet above the present sea-level. These beaches are best seen about the maritime regions of Central Scotland. Most of the seaport towns are built upon the 25-30 feet beaches. Similar beaches are found in Ireland, and likewise in England, where, however, they do not occur at a greater elevation than 20 to 30 feet above the sea. Terraces of marine erosion (Strandlinier) occur in Northern Norway at various levels, up to a height of 600 feet or thereabout. In high Arctic regions raised beaches are also common phenomena. Some of the most remarkable examples, however, occur in South America, where Darwin noticed them at various levels, from 65 feet up to 1000, and even 1300 feet (near Valparaiso), above the existing sea-level. See Dr Robert Chambers, Ancient Sea Margins (1848), and the standard works on geology.