372 PHYSICAL STEVCTUEE A^D GEOLOGY OE ATJSTEALIA, 



200 miles of ocean, tliere is another group of almost equally liigli 

 mountains which forms the island of Tasmania. The inland 

 portion of the table land slopes by a very gradual incline towards 

 the central depression, which is south and east of the true centre 

 of the continent. Thus the incline is greater and shorter for the 

 east side of Australia, and it is on this side alone we find what 

 can properly be termed a river system. The elevation of the 

 west side of Australia being only half that of the east, or even 

 less, and the distance to the central depression being twice as 

 great, we have no drainage towards the interior at all. AVhatever 

 water falls from the clouds collects in marshes, which are generally 

 &alt. The soil is composed of disintegrated granite rocks which 

 are sterile and dry, forming little better than a sandy desert. All 

 the table land is more or less interrupted with ranges of mountains 

 which do not run for any distance, and arc not sufficiently high 

 to give rise to a river system. The general direction is north and 

 south, or east and west. These mountains seem to be quite 

 independent of each other and of the general axis of the Con- 

 tinent. The most conspicuous of them is the Elinders Eange, 

 which rises at Cape Jervis on the south coast, and continues 

 without interruption for five or six hundred miles into the salt 

 lake area, where it abruptly terminates. This chain is of an 

 exceptional character. It differs from the other ranges of 

 Australia in many particulars, and is probably older. 



The base of all this table land of Australia is granitic. Isolated 

 mountains of granite crop out all through the southern and 

 western deserts. It forms the axis of the Australian Alps, and 

 the summits of a great portion of the table land on the west and 

 east coasts are of the same rock. There are also considerable 

 tracts in which the granite is replaced by upturned Paleozoic 

 f>t]'ata, mostly in the form of Slates and Schists, with an almost 

 vertical dip. It cannot be said that the granite is the cause of 

 this uplifting, for it has been mostly derived from the same slates, 

 and bears marks in some cases of stratification, inclined at various 



