The "erosion" and the contrary process of the "extension" of the coast by the action of the waves and currents of the sea must be kept apart and distinguished from a process leading to similar but not identical results, namely, the actual "crumpling" or "buckling" of the earth's crust, leading to the rising of the land surface in some parts of the globe relatively to the sea-level, and on the other hand to the sinking of the land beneath the sea in other regions. This change of the actual level of the land has continually gone on in the past, and is continually going on to-day. What are called "raised beaches" are seen on many parts of the coast. These are lines of ancient beach, consisting of sea-worn pebbles, fragments of shell, etc., forming terraces along the face of the rocks which rise from the present seashore--terraces which are now 15, 30, or more feet above the sea-level, although they must at no very distant period have been at the level of the sea. The land has risen and carried them up out of reach of the waves. Such a raised beach is seen along the rocks bordering Plymouth Sound, at a height of some 15 feet (so far as I can, at this moment, remember) above high-water mark. Owing to the fact that the rock is limestone, and is dissolved and redeposited by rain water, as a rock of sugar might be, the pebbles and shells of the old beach are all stuck together or "petrified" by redeposited limestone (carbonate of lime). Lumps of it can be carried away as specimens. Geological deposits of much older date than these comparatively recent raised beaches tell us of the rising of great masses of land. Thus, for instance, marine shells in a deposit not quite so old as our chalk cliffs and downs, are present at a height of 10,000 feet, forming part of the Alps. At one time that very spot was the bottom of the ocean, whilst other tracts of the earth's surface, now sunk hundreds of fathoms below the sea-level, stood out as continents, with hills and valleys well raised above the waters. Direct evidence of the recent sinking of the coast as distinct from its erosion is not familiar to us in England. The evidence of it is naturally obliterated, as the sinking goes on, whereas on a rising coast the evidence is as naturally preserved. But on the shores of the Mediterranean near Naples the evidence of sinking is well preserved, and has been carefully studied and recorded. The ancient Roman road is still sunk beneath the water, though the celebrated temple of Puteoli, which was formerly submerged by the sinking of the land, has reappeared by a subsequent elevation of the same area. This has not brought the site to so high a level as it had when the temple was built, as appears from the fact that the Roman paved roadway close by is still some 15 feet below the surface of the sea.