432 GREAT VALLEYS. [chap. 



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 pro- 

 jecting 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 I remarked 

 near the Weatherboard^ 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 

 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 sand- 

 stone 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, 

 as in parts of the West Indies and in the Red Sea, and 

 that their sides are exceedingly steep. Such banks, I have 

 been led to suppose, have been formed by sediment heaped 

 by strong currents on an irregular bottom. That in some 

 cases the sea, instead of spreading out sediment in a 

 uniform sheet, heaps it round submarine rocks and islands, 

 it is hardly possible to doubt, after examining the charts of 

 the West Indies ; and that the waves have power to form 

 high and precipitous cliffs, even in land-locked harbours, 

 I have noticed in many parts of South America. To 

 apply tiiese ideas to the sandstone platforms of New 

 South Wales, I imagine that the strata were heaped by 

 the action of strong currents, and of the undulations 



