464 CHARLES DARWIN 



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 pos- 

 sible 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 these ideas to the sand- 

 stone platforms of New South Wales, I imagine that the 

 strata were heaped by the action of strong currents, and of 

 the undulations of an open sea, on an irregular bottom ; and 

 that the valley-like spaces thus left unfilled had their steeply 

 sloping flanks worn into cliffs, during a slow elevation of 

 the land; the worn-down sandstone being removed, either at 

 the time when the narrow gorges were cut by the retreating 

 sea, or subsequently by alluvial action. 



Soon after leaving the Blackheath, we descended from the 

 sandstone platform by the pass of Mount Victoria. To effect 

 this pass, an enormous quantity of stone has been cut 

 through; the design, and its manner of execution, being 

 worthy of any line of road in England. We now entered 

 upon a country less elevated by nearly a thousand feet, and 

 consisting of granite. With the change of rock, the vegeta- 

 tion improved; the trees were both finer and stood farther 

 apart ; and the pasture between them was a little greener and 

 more plentiful. At Hassan's Walls, I left the high road, 

 and made a short detour to a farm called Walerawang; to 

 the superintendent of which I had a letter of introduction 

 from the owner in Sydney. Mr. Browne had the kindness to 

 ask me to stay the ensuing day, which I had much pleasure 

 in doing. This place offers an example of one of the large 

 farming, or rather sheep-grazing establishments of the 

 colony. Cattle and horses are, however, in this case rather 

 more numerous than usual, owing to some of the valleys 

 being swampy and producing a coarser pasture. Two or 

 three flat pieces of ground near the house were cleared and 

 cultivated with corn, which the harvest-men were now reap- 



