Volume 14 Australasia - dana ward's homepage

3(J8 AUSTRALASIA.islands ;at anotlier tbey are mere quagmires reflecting the glittering mirage, orelse argillaceous tracts covered with white saline efflorescences.During protracteddroiights these so-called lakes may be crossed on horseback, provided the travelleravoid the bays and inlets of the periphery, where the treacherous muds and bogsare longest maintained by the underground waters filtering through from thesurrounding lands towards the lateral creeks.From the disposition and outlines both ofLake Eyre, and of Lake Torrens,which forms its southern continuation in the direction of Spencer Golf, it seemsprobable that these now isolated basins were formerly marine inlets communicatingfreely with the South Pacific.The terminal depression, however, which is certainlythe lowest cavity on the Australian continent, still stands some 65 or 70 feet abovethe present sea-level.Another depression towards the centre of Australia is occupiedby "Lake" Amadeus, alternately a shallow lagoon, morass, or saline waste.In the arid region of West Australia there also occur several depressions of likecharacter, which are commonly designated by the name of lakes.In the thoroughly esi^lored basins, such as that of the Darling, the fluvialdischarge is so slight compared with the rainfall that some observers have soughtfor an explanation of the discrepancy in the existence of underground riversflowing beneath the surface clays, and carrying either to the sea or to somesubterranean reservoirs the greater part of the running waters. Some portion,however, of the rainfall, instead of being carried off in river beds, remains on theground in certain shallow basins, which in the Darling pasturages are known bythe name of " gilgies." On these level tracts, where the rains spread out in stagnantsheets without the force required to excavate a fluvial channel, the onlj^depressions where the water can be collected are the fissures formed in the aridsoil during the dry season.Under the action of the heavj^ downpours the sides ofthese crevasses are washed away, the bed of the cavities thus formed is levelled,and water-holes are gradually developed, which vary in depth from 4 to 5 or 6feet, and in size from a few feet to over a hundred yards in circuit. Some ofthese natural gilgies have even been enlarged by the natives, and converted intoreservoirs capable of containing considerable quantities of water.Climate.The climate of Australia is written on the surface of the land, its more salientfeatures being clearly indicated by those bare rocks, those treeless- plains andwaterless depressions which occupy the greater part of the continent. Althoughsurrounded by marine waters, Australia is of too massive a form to enjoy an insularclimate, such as that of Europe with its deeply indented seaboard. Owing to thediyness of the atmosphere, due to the slight relief and the monotonous contoursof the coastline, the meteorological conditions are essentially of a continentalcharacter.Lying half within the tropical and half in the south temperate zone, thisregion presents, from the York Peninsula to the terminal point of Tasmania, a