358 AUSTRALASIA. 



"New Zealand orographie systems, and are surj)assed even by the mountains of the 

 Solomon Archipelago. This circumstance strengthens the hypothesis, according to 

 which Australia forms a single geological unit with the lands now scattered to the 

 north and east. New Guinea, Melanesia, and New Zealand would thus be nothing 

 more than the margin of the primitive Austral continent, over half of which now lies 

 submerged beneath the intervening shallow seas. Numerous examples of similar 

 formations occur elsewhere, as in South America, in Africa, and, in a general way, 

 round the great Oceanic basin from the Cape of Good Hope to Cape Horn, where 

 the loftiest crests also rise immediately above profound marine abysses. 



Physical Features. — Mountain Systems 



As in other Australasian regions, the highest mountains on the mainland occur 

 in the neighbourhood of the seaboard and on the side facing the deep Pacific 

 waters. The chief continental crests are disposed in such a way as to form an 

 outer crescent sweeping round from York Peninsula to Wilson's Promontory, 

 over against Tasmania. Beyond this elevated rim the land falls so uniformly as 

 to suggest to the early explorers the existence in the interior of a " Caspian " 

 depression, into which flowed all the surrounding streams. But instead of this 

 imaginary central sea there exists nothing beyond a few small basins without any 

 outflow, while nearly all the important rivers flow directly to the coast. Never- 

 theless the plains traversed by them stand at a very low level, in consequence of 

 which disposition of the land the seaboard has been excavated far into the interior 

 both on the north and south sides, where have been respectively developed the 

 Gulfs of Carpentaria and Saint Yincent. Between these two indentations, which 

 are the largest on the whole continental periphery, the intervening plains scarcely 

 anywhere exceed an altitude of 500 feet above sea-level. West of this depression 

 the surface aojain rises, and towards the centre of the continent several of the 

 summits exceed 3,000 feet in elevation. 



The chief range, known as the Australian Alps, begins in Yictoria, and after 

 presenting its convex side towards the south-east, trends round to the left and is 

 continued by other chains northwards. The Yass, a headstream of the Murray, 

 is regarded as the northern limit of the Australian Alps proper, which have a total 

 length of about 250 miles. These highlands deserve the name of Alps less for 

 their altitude than for the large number of their collective groups, spurs, offshoots, 

 lateral or parallel ridges. They are almost everywhere of easy access, the most 

 rugged escarpments being usually situated about midway between base and sum- 

 mit, Avhile higher up the slopes are more gently inclined, and extensive grassy or 

 sparsely wooded plateaux form the pedestal of domes and crests which may be 

 ascended even on horseback. The culminating peak, Mount Townshend, in the 

 Kosciusko group. New South Wales, attains a height of 7,350 feet. 



In many of these upland valleys the snows never melt, and in winter from 

 May to November even the plateaux remain shrouded in a white mantle. A few 

 névés are found in the higher ravines of the Kosciusko Mountains, and traces of 

 ancient glaciers in various parts of the range. In the Bogong Hills (6,630 feet), 



