362 AUSTRALASIA. 



heat and cold, wind and rain, and in several places the surface has been excavated 

 many tens and even hundreds of yards, leaving here and there masses of harder 

 rocks, which indicate the original level of the now vanished formations. In 

 north-west Australia lies the region to which Gray has given the name of " Pillar 

 Land," from the myriads of sandstone columns rising above the surrounding plains 

 which have been irregularly excavated. This region is carpeted with flowering 

 plants and festooned with belts of verdure, while the work of erosion is still con- 

 tinued by running waters partly flowing below the surface. 



About the very centre of the continent stands another of these geological 

 witnesses, which is known as "Chambers's Pillar," and which rises 150 feet above 

 an eminence itself about 100 feet higher than the surrounding plain. This 

 column, one of the most regular formations of the kind on the surface of the globe, 

 forms a conspicuous landmark much utilised by the early explorers as a rallying 

 point, and convenient site for a cache or storehouse of provisions. It is about ten 

 feet by twenty in cross section, of nearly equal compass from top to bottom, and 

 formed of a soft white sandstone like the hill on which it stands. The upper part 

 of the pillar is of a red tint, and its preservation is perhaps due to the greater 

 hardness and durability of this topmost layer (Wallace). 



Like the Sahara, the Australian desert has its region of dunes stretching west 

 of the overland telegraph on the north-west continental slope. Here the chains 

 of sandhills follow each other with perfect regularity, rolling away like the waves 

 of the sea for a distance of about 350 miles in the direction from east to west. 

 Consisting entirely of red particles, without a blade of grass to relieve their fierce 

 glare, these dunes are described by Sturt as producing a "terrible" effect, and no 

 traveller ventures to traverse them without a sense of awe. Beyond this dreaded 

 region a few verdant and flowery oases are seen here and there in the dreary 

 wilderness. The aspect, however, of the Australian desert changes with the dry 

 and wet seasons, so that the descriptions of the same district by different explorers 

 often present great discrepancies. 



The observations made by geologists on the main features of the continental 

 periphery lend much probability to the hypothesis of a general upheaval of the 

 Australian seaboard. Its shores, after having been submerged under the waters, 

 which at one time covered about half of the surface, were again gradually upr lised 

 above the level of the surrounding seas. The coasts are fringed by upheaved 

 beaches, in which are embedded banks of shells similar to those still surviving in 

 the neighbouring waters. Numerous lakes, which were, till recently, marine 

 inlets, have preserved their oceanic fauna, while others have been gradually 

 changed to freshwater basins, or have even been completely evaporated. Shoals 

 and reefs formerly concealed below the surface now show their black rocks above 

 the level of the sea. 



A careful study of the whole region stretching to the north of Spencer Gulf 

 leaves no doubt that this tract of dry land at one time formed an archipelago with 

 numerous islands separated from each other by shallow straits. Bass Strait itself, 

 which forms the southern limit of Australia proper, would be changed to dry land 



