xvili.] LAND AND WATER. 303 



The total area of this great surface of dry land, which, 

 with its islands, constitutes the Old World of geographers, is 

 22,392,430 square miles (CCXLIX. nearly). Although it is 

 surrounded by water on all sides, it no longer receives the 

 name of an island, but is termed a continent; or is more 

 usually regarded as composed of the three continents of 

 Europe, Asia, and Africa. Between the two former, there 

 is no natural demarcation, and they would be, for most 

 purposes, better spoken of as one region, under the name of 

 Eurasia. But Africa is obviously marked off from the rest, 

 in consequence of its connection with Eurasia only by a very 

 narrow neck of land, the Isthmus of Suez, now cut through 

 by the Suez Canal. 



The surface of Eurasia and of Africa is divided into 

 river-basins by water-partings, and is diversified by elevations 

 and depressions, like those which have been met with in the 

 British Islands, but on a scale proportioned to its relative 

 magnitude. It would be beside the purpose of this work 

 to study their features in detail ; but the broad aspects of 

 the great system, of which the Thames basin forms an 

 insignificant part, may be sketched. 



The mountains of England, as we have seen, stand apart 

 from its main water-partings; but those of the Eurasian 

 continent coincide with the lines of separation of the great 

 water-sheds. A sinuous band of highlands, which often rise a 

 mile above the sea-level, and the highest peaks of which some- 

 times attain between five and six times that height, stretches 

 almost continuously from the waters of the Atlantic in the 

 west, to those of the Pacific on the east of the Eurasian 

 continent. (See map, Fig. 91.) 



At the western end, this highland zone is narrow and not 

 very high, and, as the mountain range of the Pyrenees, 

 separates France from Spain ; these are followed by the 



