THE DESERT SANDSTONE. 311 



Muirhead, Graham, Leake, Gambier, and others too numerous to 

 mention, which occur a little way inland. 



The vast accumulations of sandstone in the interior without 

 any fossils, diversified with canons, gorges, precipices, plateaux, 

 and table-topped hills, indicate such an origin as I am suggesting, 

 if we can only satisfy ourselves that the material of which this 

 sand is composed is such as may have been derived from volcanic 

 sources. The evidence that appears to me to bear upon the matter 

 I will now place before my readers. 



In my recent travels through Java, my attention was specially 

 directed to the origin of the sandstones met with in that very 

 volcanic island. The first thing that took my attention on landing 

 in Java was the sand upon the beach, which was black and as 

 unmistakably volcanic as anything could well be. No one could 

 misunderstand its character, which spoke plainly of subterranean 

 fires ; just, in fact, like very recent volcanic ejectamenta on the 

 latest extinct craters of South Australia. What this deposit 

 would become in a few years time was plainly evident in the older 

 beds. Close by Banjuwangi is the large active volcano of Rawun 

 over 10,000 feet in height, and with a crater of more than five 

 miles wide. As one ascends its torn and rugged sides the huge 

 crevasses and terribly precipitous gullies of 1,000 feet and more 

 reveal immense masses of beds deposited by ancient eruptions. 

 In colour, in consistency, in material, and in stratification they 

 very strongly reminded me of the Desert Sandstone ; but I should 

 be far from considering this resemblance as a sufficient proof of 

 their identity. There is not a grain of sand cast forth from the 

 bosom of the earth that is not stamped with marks innumerable 

 to show the nature of its origin. As truly as every coin minted 

 bears a stamp to mark the place of its coinage, so each tiny grain 

 of dust bears its impress unmistakably. It is almost proverbial 

 to say that grains of sand are as like one another as things can 

 well be. But direct the tube of the microscope upon them and 

 what a number of differences are revealed. The volcanic grain 

 with its freshly molten certificate of character, its glassy inclusions, 

 its gas-cavities, and its optical properties, has entirely peculiar 

 qualities of its own which no other grain of sand in the wide world 

 can pretend to. It is true, however, that if it has lain exposed to 

 chemical influences from remote antiquity, its genealogy may be 

 so obscured that only the most experienced eye could trace it, and 

 there are very many sandstones, whose origin, volcanic or no, 

 cannot be decided. But for modern volcanic sands no such thing 

 is possible. The finest volcanic dust (indeed the finer the better) 

 of anything like modern geological times is one of the easiest 

 things to detect, and few could be mistaken in it. 



In my paper on the Hawkesbury Sandstone, sands and their 

 characters became a special subject of investigation. Thus my 



