64 THE HAWKESBURY SANDSTONE. 
entirely quartzose with a few scales of mica. 
Messrs. Sorby and Phillips have both made sand particles the 
subject of special study. The latter has found that wind-blom 
sands have the grains nearly all rounded, especially if they have 
been exposed to the action of the wind for any time. The sands 
of the Egyptian deserts are all rounded. On the other hand, Mr 
Phillips has found that fine sands taken from the beds of streams 
are always an: , and this even where there is good proat 
that they have been borne great distances by the water. The 
explanation of this fact seems easy to find. In the air thers 
nothing to prevent the friction of the particles on one ores 
; : vee | 
the end of this paper will be found all the observations which I 
the conclusions of Mr. Phillips. I have microscopically examinel 
all sands from all the rivers and creeks I have come across The 
smaller particles are never entirely rounded unless the fragments 
is nearly all composed of abraded particles, but there are ane 
siliceous particles occasionally which I shall subsequently a 
It lcs Ae remarked that I have said some wind-blowns' 
are a because the grains composing already 
referred toon the Burdekin River were not at all abraded. iad 
particles with very few exceptions were quite angular. y 
. the 
Nature of the sand.—Now, in applying these principles Oi 
wkesbu: : ’ plying ca jh 
ury sandstone we find we are stopped by @ dificulty f bs 
portions of the rock. Any one ing across - 
cannot fail to have lieed the ae of the sandstone hyo : 
outings, A closo examination will show that this®°™ 
