Mountains.— There is no active volcano in the Commonwealth but some craters show signs of only recent extinction and of intermittent previous eruptions. A mountain range varying from 100 to 200 miles in width outlines the eastern and southern border of the continent; and, broadly speaking, all the rivers of Southern Australia take their rise in this Great Dividing Range. The Australian Alps, in the southeast part of the Dividing Range, contain the highest mountain summits in Australia— Kosciusko (N.S.W.), 7,308 feet; Mount Bogong (Vic.), 6,508. These are the most elevated points on the continent. In Queensland peaks in the Be lenden Tier Range rise to 5,400 feet, and in other parts of the state are several eminences of about 4,000 feet., In South Australia the loftiest range is the Flinders — Mounts Remarkable and Brown, 3,100 feet each; and the principal eleva tion in the Gawler Range in the northwestern interior is about 2,000 feet. In Western Aus tralia Mount William (3,000 feet) in the Darl ing Range, and Ellen's Peak (3,420 feet), are the loftiest. Tasmania is very mountainous— highest peaks, Cradle Mountain 5,069 feet, and Ben Lomond 5,010 feet.
Rivers and The Australian •Father of Waters* is the river Murray, which with its chief tributary, the Darling, flows 2,400 miles before reaching the Southern Ocean on the South Australian coast, and with its Queensland extensions has in favorable seasons a length of about 3,000 miles navigable by small steamers. It is under agreement between the riparian states (South Australia, Victoria and New South Wales), now being looked to to im prove navigation, and also to provide water for irrigation. In the Northern Territory, as well as elsewhere, some of the rivers are of large volume, and are navigable for compara tively short distances. On the east coast are the Hunter, Clarence, Brisbane, Fitzroy and Burdelcin; on the west the Swan, Murchison, Gascoyne, Ashburton and De Grey; on the north the Fitzroy, Victoria, Flinders and Mitchell. A considerable river on the interior is Cooper's Creek, or the Barcoo, which falls into Lake Eyre, one of a group of lakes on the south side of the continent having no outlet, and, accordingly, salt. The principal of these are lakes Eyre, Torrens and Gairdner, all of which vary in size and saltiness according to the season. Another large salt lake of little depth, Lake Amadeus, lies a little west of the centre of Australia. Various others of less magnitude are scattered over the interior.
Speaking wherever the land is elevated the rainfall is good. It varies from about 70 inches annually in the tropical zone to three or four inches or even less, in the arid interior regions, and in the southern part to about 40 inches. The fall diminishes in close relation to the decline in the elevation of the land, allowing for coastal in fluence in the south, and tropical or sub-tropical conditions in the north.
The climate of Australia is gen erally temperate, and in summer hot and dry, especially in the southern and central parts, but very healthy. In the tropical portions heavy rains fall and in most of the coast districts there is a sufficiency of moisture but in portions of the interior the heat and drought are some times extreme. The air is, however, so ex hilarating that even 120° F. of shade heat in Australia is less oppressive than 90° in London, Paris or New York, and cases of sunstroke are rare. This dry-hot atmosphere is especially recommended by medical men as an essential for sanitoria for sufferers from lung disease, and among the artesian waters in some of the arid country are highly mineralized springs with valuable medicinal properties. The dangers of drought, too, are being largely reduced by the rapid extension of the artesian boring area. At Melbourne (Vic.) the mean temperature is about Sydney (N.S.W.), about 63; Ade laide (S.A.), 61; Perth (W.A.), 64; Brisbane (Q.), 68; and Port Darwin (N.T.), 82 (tropi cal) ; Hobart (Tas.), 55. In the mountainous and more temperate parts of Australia snow falls in winter (June, July and August), and long remains unmelted on portions of the Great Dividing Range, as well as in Tasmania. Prac
tically, however, at no time of the year is it possible to skate on ice in any division of the Commonwealth. Australia is essentially a warm country throughout, but the winters are keen and bracing.
Fauna
The distinguishing fea tures of the extinct fauna (of which most in teresting discoveries have been made) are specially worthy of note. In the mammalian class the great majority are marsupials, though the dingo and the whale (non-marsupial) are also found in a fossil state. Fossil remains of birds, reptiles (such as crocodile, monitbr), turtles and fishes, have also been unearthed, some in the banks of the rivers in the interior. This indicates that the ancient vertebrate fauna of Australia was very similar to what it is now. The preponderant type of mammal was mar supial. In most respects, however, the species and even the genera were different, and many (such as diprotodon, nototherium, and the giant kangaroo) were much larger animals and of a more generalized type than exist at present. One living type (a wombat) is precisely of the same species as is found in a fossil condition. Regarding the probable cause of the destruc tion of the extinct animals, it is impossible to give a general statement applicable to such a wide-stretching country as Australia, any more than such a statement could be applied to other countries where there has been a wholesale dis appearance of once numerous groups. Changes of climate or physical conditions rendering the country or district unsuitable for their main tenance; over-specialization in structure caus ing the types to be incapable of adapting them selves to changed conditions; not impossibly the ravages of infectious or parasitic diseases — all these have had their effect. As a prob able explanation in the special case of the Lake Callabonna fossils (a remarkable discovery in South Australia) the following occurs in