Origin of ShaiiBs, 
1 15 
long grass on the lower Macquarie, from the turbid 
and flooded river more than a mile away. It was 
certainly somewhat in this way, the undergrowth 
around the ancient Triassic lagoons that arc now beds 
of shale, more or less cleared the waters of the coarser 
materials and allowed the finer sediments to pass on. 
The speed of the running water is checked also 
in flowing through a thick undergrowth of vegetation, 
and the heavier materials that are being carried alonar 
are at once dropped to the bottom. The finer particles 
held in suspension are not deposited until the waters 
cease to flow on reaching a lake or lagoon. 
It has been stated, in passing, that Tenison- Woods 
himself abandoned the theory as to the yEolian origin 
of the Hawkesbury Sandstone. Personally, I am 
inclined to the opinion that the theory, though not 
accepted by geologists, was, in the words of Professor 
Liversidge, a a valuable and suggestive paper, and one 
of the most interesting brought before the Itoyal 
Society on geological matters for a long time.” And, 
after all, it may yet be discovered there was a germ 
of truth in the views of Tenison- Woods. Writing on 
this subject, Dr. Taylor says: “L hold that this theory 
of Tenison- Woods, whether ultimately proved or not, 
is a gain to speculative science. I have long thought 
that Solar denudation has not been sufficiently taken 
into effect in Physical Geology. Twenty years ago 
it was the fashion to give the sea the predominance 
as a denuding agent. That was in the geologically 
