During Post-Miocene Times. 3 



formation over hill, plain, and valley, its uniform character, 

 and the peculiar rounded and water-worn nature of much of 

 the material composing it, are features that appear to require 

 for their production some cause having a much more 

 extended, uniform, and powerful action than can well be 

 ascribed to river floods" (Selwyn's Notes on Vict, p. 25). 

 Similar opinions have been expressed by Murray (Geo. Swr. 

 Rep., p. 68), Krause (Gold, p. 650), Brough Smyth (Goldfields, 

 p. 154), Howitt, and others. 



When we reflect upon the transport power of running 

 water, as it is exemplified around us, we must feel still more 

 dubious of the fluvial origin of these drifts. If we turn to 

 the well-observed rivers of Great Britain, we find that three 

 miles an hour is the maximum speed of the Thames, the 

 Clyde, and the Tay, and that one and a half miles per hour 

 is a moderately swift current (Stevenson on Reclamation, p. 

 18). Further, we see that a velocity of one and a third 

 miles per hour will transport pebbles one inch in diameter, and 

 one of two miles per hour pushes along the bottom slippery 

 stones of the size of an egg. Now, as three miles is the 

 maximum speed of any British river, and as a two-mile 

 current cannot propel stones larger than an egg, no British 

 river could transport such boulders as encumber our drifts. 

 And as there are no Victorian rivers which exceed the 

 swiftest British rivers — the Tay, for instance — in the strength 

 and speed of their currents, these boulders must, in an equal 

 degree, be beyond their powers also. But if we suppose 

 that the Victorian rivers were, in late tertiary times, much 

 larger and swifter, so as to equal the swiftest known streams, 

 would they even then be able to create these conglomerates ? 

 I think not ; for whatever speed our rivers may have had 

 down to the foot-hills, they could not have run swiftly across 

 the flat plains, and these deposits are found far out upon 

 them, as far away as the Murray banks at the Campaspe, and 

 even out on the Darling. These vast plains have at the out- 

 side a slope of two feet in the mile, and the Murray, between 

 Albury and Echuca, falls less than one foot (B. Smyth's Gdd- 

 fields, p. 206). What evidence have we that such a small 

 incline could endow a river with the power to transport, 

 however slowly, these heavy conglomerates for long distances 

 across wide plains ? Absolutely none that I can discover. 



If we turn to mountain torrents as an efficient cause, we 

 find that they may have for short distances, and during brief 

 periods, a speed of from 18 to 20 miles per hour (Geikie's 



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