1839.] GEOLOGICAL FORMATION. 223 



been entertained, when the continued discoveries which were 

 made, disclosed the existence of numerous rivers and streams, 

 whose courses seemed to tend towards some great internal 

 isea. All these ideas, however, are now known to be errone- 

 ous. Although, as remarked by Mr. Oxley, in the narrative 

 of his adventurous tour,* " the whole form, character, and 

 composition of this country, is so singular, that a conjecture 

 is hardly hazarded before it is overturned," — still, it seems 

 but reasonable to infer, that Australia, so far as it respects 

 the interior, is in an inchoate or imperfect state, or, in other 

 words, yet in process of formation. All the masses of moun- 

 tain land, and the detached peaks, between the great ranges 

 at either extremity of the continent, are separated by monot- 

 onous levels, or dead flats, singularly deficient in vegetation, 

 which wear every appearance of having been recently sub- 

 merged beneath the waters of the ocean. 



Plutonic rocks are tolerably abundant in the principal 

 ranges, yet the interior, though exhibiting so much that is 

 anomalous in character, is apparently of Neptunian forma- 

 tion. The isolated peaks are composed of sandstone, and 

 the soil of the flats is loose and porous, and strongly impreg- 

 nated with salt. Small salt-lakes, or brine-pits, are very 

 common in the dead levels. These low grounds are subject 

 to inundations ; but they are by no means regular, and are 

 usually succeeded by long periods of drought. Box trees, 

 polygonum, reeds, kangaroo grass, and other marsh plants, 

 and trees and shrubs that delight in excessive moisture, 

 taking root in the soil formed of the debris washed down 

 from the high lands, spring up in the low wet places after 

 each overflow, live their brief life, and wither and die. Other 

 plants, to which the fertilizing slime and decomposing vegeta- 

 tion, though lacking humidity, afford sustenance enough, 

 now make their appearance; stately rows of yarra trees, 

 like files of soldiers, line the channels of the rivers, and the 

 bights are crowded with dense thickets of eucalypti; yet all 

 these are, in their turn, destroyed by the constant exposure 



* Page 81. 



