298 The Realm of Nature CHAP. 



'to have been diverted by sand-dunes ( 307), may still be 

 traced. At a more remote period the Aral Lake was part 

 of a large sea which covered the Caspian basin and com- 

 municated with the Mediterranean, and in Quaternary 

 times spread over the low watershed of the Ob to the 

 Arctic Sea. 



383. Indian Peninsula. A great low plain extends 

 along the base of the Himalaya, separated by a gentle 

 ridge into a south-western slope traversed by the Indus ^n 

 its way to the Arabian Sea, and a gentler eastern slope, 

 along which the Ganges ( 318) flows to the vast delta 

 which it shares with the Brahmaputra. An ancient 

 and much denuded plateau largely built up of volcanic 

 rocks fills the southern part of the peninsula. This plateau 

 is loftiest on its western edge, where it sinks in abrupt 

 terraces to the sea, presenting a mountain-like wall known 

 as the Western Ghats. The more gentle slope to the east 

 has been cut by numerous rivers into wide valleys, and the 

 broken plateau edge forms a lower and less regular line of 

 heights more remote from the sea, called the Eastern 

 Ghats. The coast-line on both sides is remarkable for 

 its unbroken character and the gentle shelving of the 

 beach. 



384. Europe, a bunch of peninsulas thrust out into the 

 'Atlantic Ocean, is the only great land-mass not crossed by 

 one of the tropics, and from its well-marked sea-climate it 

 may be appropriately termed the Temperate Continent. 

 An axis of true mountains of elevation runs through 

 Southern Europe, and another forms the low belt of the 

 Urals on the boundary with Asia. A rim of ancient 

 plateaux worn into mountains of denudation marks the 

 north-western border in Scotland and Scandinavia. 

 Within this elevated frame the land is a wonderfully 

 uniform low plain, fully half of the continent being less 

 than 600 feet above the sea. Only one-sixth of the 

 surface has an elevation greater than 1500 feet. The 

 lines of elevation have a comparatively slight share in 

 determining the slopes, which exhibit none of the typical 

 continental simplicity. 



