290 _ Scientific Intelligence. 
ous” idea, that simple ee water has been the agent; and if so, 
was it fr oe water, or the 
The forms of these er are as remarkable as their extent. Major 
Mitchell ann that Cox’s River rises in the Vale of Clywd, 2150 feet 
above the sea, and leaves this expanded basin through a gorge 2200 
yards wide, flanked on each side by rocks of horizontally stratified 
__ seateageea eight hundred feet high: here it joins the Warragamba. 
of its tributaries rise * a height of 3500 feet above the sea, — 
the ravines they occu ver an area of 1212 square miles. m 
this he calculates that one ieee and thirty-four cubic miles of dom r . 
have been removed from the valley of the Cox.* The facts observed | 
by us are sufficient to substantiate the general result, allhough we can- P 
not add definite estimates of our own. ‘The Kangaroo Valley is another 
example of a valley, two to three miles in width, and a thousand feet 
to eighteen hundred deep, opening outwar through a comparatively 
narrow gap: and by a rough calculation from our own examinations, 
and the map of Major Mitchell, the amount of rock necessary to fill the 
valley is a toa pe mek twelve miles long, two miles . 
length. This is but a small sonst helene; sions! with those J 
of the interior, Mr. Darwin remarks upon this peculiarity of form,— { 
bays along the c 
In studying he nie of these valleys, we have then to consider the 
following particulars :— 
1. Their high, precipitous, or vertical walls of stratified sandstone, 
and ~_ — areas at bottom—excepting where the descent of the 
stream i 
2. Their frequent great breadth towards their head, ie bape they 
are often very narrow, like a large bay with a small e 
3. absence of all traces of the hingeuniia siaesstel which 
could have filled these valleys. 
culty with one who admits time te ‘be an element which a roctegil has 
indefinitely at command. But the subject admits of full a 
as we believe, without making any improbable te nm on this point. 
We need but refer to a former page, in which we have discussed the 
~ subject of valley-making by denudation among the Pacific islands,? to 
show that New Holland, after all, is not the most remarkable land in 
the world for valleys of denuda tion. 
should consider that the rock material is far more yielding than 
that of basaltic Tahiti. Indeed the whole rock, from the uppermost 
layer to the deposits below the coal, is remarkably fragile, considering 
* Expedition into Australia, ii, 352, "+ See this volume, p. 48. 
bat 
