76 PHYSICAL GEOGKAPHY OP THE SEA. 



bergen, immense glaciers frequently fill the valleys that open on 

 the sea, descend even beyond the water's edge, and, as they 

 move along, their overhanging masses separate from their base 

 and plunge into the deep with a crash louder than thunder. 

 The icebergs that drift about the Arctic seas, and are annually 

 conveyed by the currents into lower latitudes, are formed in 

 this manner. Huge blocks of granite, detached by atmo- 

 spherical vicissitudes from the higher mountains and precipitated 

 on the surface of the glaciers, frequently float on the broad back 

 of an iceberg far away from the spot where they seemed rooted 

 for eternity. As their crystal support melts away in its progress 

 to warmer climes, these rocky fragments, which have been 

 appropriately named erratic blocks, fall to the bottom of the sea 

 hundreds or even thousands of miles from the starting point of 

 their journey. Thus the great bank of Newfoundland is covered 

 with stones from distant Greenland, raised high in the air by 

 volcanic power myriads of years ago, and now condemned to an 

 equally long repose below the surface of ocean. When will 

 they rise again above the waters, and what further changes will 

 they have to undergo ere their compacted atoms resolve them- 

 selves into dust and assume new forms ? But, however remote 

 their dissolution, it will inevitably come, for Time is all-powerful, 

 and has an eternity to work out his changes. 



The large blocks of stone that so wonderfully migrate on the 

 wandering iceberg form but a small and insignificant portion of 

 the terrestrial spoils which are transported to ocean by the 

 returning waters. Every river is more or less laden with 

 earthy particles which its current carries onwards to the sea 

 and deposits at its mouth. In course of time their accumu- 

 lation, as I have already mentioned, forms large tracts of fertile 

 territory encroaching upon the maritime domains. 



I shall end with a few words on the influence of forests in 

 attracting or retaining the atmospherical moisture, as it is a 

 subject of great importance in the economy of nations, and 

 shows us how much it is in the power of man to improve or to 

 defeat the provisions of nature in his favour. 



Forests always cool the neighbouring atmosphere, for their 

 foliage offers an immense warmth-radiating surface, so that the 

 vapours readily condense above them and descend in frequent 

 showers. At the same time their roots loosen the soil, and the 



