BY THE REV. J. MILNE CURRAN, F.G.S. 183 



and Phillips all agree that blown sand, by its rounded and abraded 

 particles can be dihtinguished from river-borne and other suba- 

 queous sands. In the case of the Hawkesbury sandstone the once 

 abraded and rounded grains may have been subjected to such 

 conditions as would induce subsequent crystallisation. But we are 

 aware of no means by which angular or crystalline particles could 

 become rounded after deposition, A few rounded and abraded 

 grains, even when the great mass of the rock is crystallised, would, 

 to my mind, go far to uphold the -^olian theory, more especially 

 when considered in the light of other facts equally significant. 

 Rounded and abraded grains are to be found in the Dubbo sand- 

 stones. The slide I exhibit is a fairly typical one. The sand grains 

 were well washed and spread on paper previously brushed over with 

 gum. Portions containing seemingly abraded particles were then 

 cut from the sheet. 



Mr. J. Milne, in his notes on the Sinaitic Peninsula (Q. J. G. 

 Soc, Vol. XXXI., p. 18.) mentions the definite character which 

 blown sand gives the scattered stones in the desert about Nackhl. 

 All have a peculiar polish, looking as if they had been smeared 

 with grease, a lustre nearly represented in the fractured surface of 

 some specimens of witherite. Should these stones, he remarks, 

 become buried, futui'e investigators will find in them marks as 

 clearly indicative of their origin as the rounded forms of water- 

 worn pebbles or the angular and scratched faces in beds of glacial 

 drift. Just as we infer from the lattei", the existence of former 

 glaciers, so they will infer the former presence of deserts and 

 " sand-drifts." The pebbles in the Dubbo sandstones, when 

 cleared of the minute particles (quartz or decomposed felspar) 

 adhering to the surface, have in very many instances that I have 

 noticed, an appearance that rolling in water could never give them. 

 But whether these may not be water- worn gi'ains chemically corroded 

 on the surface I am not prepared to say. 



Another point worth considering Is the great difference between 

 the normal sandstone and those portions of it, which have 

 undoubtedly been deposited in water. We often see beds of 

 shale which split up into thin laminae. This fissile structure is due 



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