i536.] , GKEAT VALLEYS. 4.?9 



a gorge 2200 yards in Avidtli, and about 1000 feet in depth. 

 Other siniihir cases might have been added. 



The first impression, on seeing the correspondence of tlie hori- 

 zontal strata on each side of these valleys and great amphithea- 

 trical depressions, is that they have been hollowed out, like other 

 valleys, by tho action of water ; but when one reflects on the enor- 

 mous amount of stone, which on this view must have been re- 

 moved 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 promon- 

 tories projecting into them from the platforms, we are compelled 

 to abandon this notion. To attribute these hollows to the pre- 

 sent alluvial action would be preposterous ; nor does the drain- 

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

 Vreatherboard, 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 AVales, the nume- 

 rous, fine, widely-branching harbours, which are generally con- 

 nected 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 AVest 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 cur- 

 rents 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 wavea 

 have power to form high and precipitous cliffs, even in land- 



