THE DESERT SANDSTONE. 299 



" It will appear, therefore, that as far as I have seen, the Desert 

 Sandstone so called, is confined to numerous small patches of a 

 newer formation of moderate thickness, which does not cover the 

 older rocks to any large extent. Yet this character would not be 

 suspected from its aspect as seen from a distance. T do not 

 wonder in the least at earlier explorers having been led into error 

 with regard to it. When one ascends to the summit of any- 

 moderate elevation, the sloping base, white cliffs, and flat summits 

 of these hills are conspicuous objects, and there extend from these, 

 level plains of apparently unlimited extent. But none of the 

 hills are high enough to command an extensive view : if they did, 

 other hills would be seen cropping out. The mistakes which have 

 occurred have been for want of careful measurements, or giving 

 descriptions from distant views rather than from actual exploration 

 and a close examination of the nature of the rocks. I have also 

 had the advantage of the 125 miles of levels taken for railway 

 purposes. 



"It must be also borne in mind that the magnesian and 

 sandstone formation never rises to the height reached by the 

 palaeozoic and metalliferous rocks. Thus Mount Wells (mica 

 slate, with tin and copper veins) is about 900 feet above the level 

 of the sea ; Springhill — gold mine, 800 feet ; the Union, 700 feet ; 

 Jensen's, 800 feet, and so on. None of these heights are ever 

 attained by the flat-topped table-land. So far, therefore, from 

 much of the auriferous formation being covered by it, from its 

 nature and elevation that formation is far more likely to crop 

 out above it. 



" From what has been said, it appears that the term Desert 

 Sandstone is a misnomer. Whether the formation is the same as 

 that which was described under that name by Mr. Daintree, in 

 Queensland, is not certain. There are here three kinds of 

 rock : — (1) A red sandstone, composed almost entirely of rounded 

 grains of sand and ferric oxide ; the appearance of these grains 

 and the stratification of the rock show a desert origin, such as 

 blown sands present. (2) Magnesite and silicate, and ferro- 

 silicate of magnesia ; this rock is pure white and yellow, or 

 mottled fiery red. These rocks I believe to be derived from the 

 decomposition of fine volcanic ash, containing much olivine, or 

 otherwise rich in magnesia. South of the Edith River there is a 

 large volcanic area, with high basaltic hills and much vesicular 

 lava, all rich in olivine. When these volcanoes were in activity 

 (in Miocene times T), the fine dust from the ashes covered a large 

 area ; thus we find these flat-topped cliffs of magnesite lying on 

 granite rocks and on slates (Mount Shoobridge). (3) The third 

 formation included under the name of Desert Sandstone, is a 

 fluviatile conglomerate ; it is only found on the banks of streams ; 



