THE HAWKESBURY SANDSTONE. 83 
Conglomerates—The only question which still remains to be 
dealt with in dealing with these sands is the presence of pebbles 
and conglomerates. These latter cannot be attributed to win 
Let it be further borne in mind that except in the lowest strata, 
bles are rare, and those that are found are very small and only 
such as would be easily carried by the wind. 
_ Whatever be the origin of the conglomerates, those of large 
the base of the forma- 
All the other instances can well be accounted for by (1) the action 
of creeks, of which there must have been many ; (2) extraordinary 
Storms or tornadoes ; (3) concretionary action. That the latter 1s 
hot an insignificant cause can easily be seen from the experiments 
Stanislaus Meunier,* who found by the infiltration of chloride 
of lime and silicate of potash through heated loose sand, that 
‘oheretions were rapidly formed. Accident revealed another 
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_ “Ame through the roof deeply corroded the mass, and the water 
: flowing from the iron on to the stone deposited so much hydrated. 
digi iron on to the sand that it became an irregular co 
mass, portions of which were exceedingly hard, like iron.T 
: os 
- Prease scientifique des deux Mondes, tome 2, de 1866. 
_ t Les causes actuels en Géologie, p. 298. S8vo. Dunod, Paris, 1880. 
