THE VOYAGE OF THE BEAGLE 463 



natural and partly made by the owner of the land, they can- 

 not escape ; for this valley is in every other part surrounded 

 by perpendicular cliffs, and eight miles lower down, it con- 

 tracts from an average width of half a mile, to a mere 

 chasm, impassable to man or beast. Sir T. Mitchell states 

 that the great valley of the Cox river with all its branches, 

 contracts, where it unites with the Nepean, into a gorge 

 2200 yards in width, and about 1000 feet in depth. Other 

 similar cases might have been added. 



The first impression, on seeing the correspondence of the 

 horizontal strata on each side of these valleys and great 

 amphitheatrical 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 allu- 

 vial action would be preposterous; nor does the drainage 

 from the summit-level always fall, as I remarked near the 

 Weatherboard, into the head of these valleys, but into one 

 side of their bay-like recesses. Some of the inhabitants re- 

 marked to me that they never viewed one of those bay-like 

 recesses, with the headlands receding on both hands, without 

 being struck with their resemblance to a bold sea-coast. This 

 is certainly the case; moreover, 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 

 depressions on a wide platform, and left mere gorges at the 

 openings, 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, 



