8 ANNIVERSARY ADDRESS, 
As bearing on the interesting theory propounded by the Rev. 
J. Tenison-Woods, in his paper on the Geology of the Hawkes- 
bury Sandstone, to which I have alluded, I should like to quote 
Mr. Darwin’s impressions on visiting the remarkable scenes_pre- 
sented to his observation in crossing the Blue Mountains. He 
says : “The first impression, on seeing the correspondence of the 
horizontal strata on each side of these valleys and great amphi- 
theatrical depressions, is that they have been hollowed out, like 
other valleys, by the action of water ; but when one reflects on 
the enormous amount of stone which on this view must have been 
removed through mere gorges or chasms, one is led to ask whether 
these spaces may not have subsided. But considering the form of 
the irregularly branching valleys, and of the narrow promontories 
projecting into them from the platforms, we are compelled to 
abandon this notion. To attribute these hollows to the present 
alluvial action would be preposterous, nor does the drainage from 
the summit-level always fall, as is remarked, near the Weather- 
board into the head of these valleys, but into one side of their 
bay-like recesses. Some of the inhabitants remarked to me that 
they never viewed one of these bay-like recesses, with the head- 
lands receding on both hands, without being struck with their 
resemblance to a bold sea-coast. This is certainly the case. More- 
over, on the present coast of New South Wales, the numerous fine 
widely-branching harbours, which are generally connected with the 
sea by a narrow mouth worn through the sandstone coast cliffs, 
varying from one mile in width to a quarter of a mile, present a 
likeness, though on a miniature scale, to the great valleys of the 
interior. But then immediately occurs the startling difficulty, 
why has the sea worn out these great though circumscribed de- 
pressions on a wide platform, and left mere gorges at the open- 
ings, through which the whole vast amount of triturated matter 
must have been carried away? The only light I can throw upon 
this enigma is by remarking that banks of the most irregular 
forms appear to be now forming in some seas, as in parts of the 
West Indies and in the Red Sea, and that their sides are exceed- 
ingly steep. Such banks, I have been led to suppose, have been 
