Art. L — On the Evidences of a Glacial Epoch hi Victoria 

 During Post-Miocene Times. 



By G. S. Griffiths. 



[Bead 13th March, 1881.] 



Having had occasion to pay frequent visits to our goldfields, 

 the boulder washes which accompany many of our alluviums, 

 especially the richer ones, have always excited my wonder 

 and curiosity. The heavy boulders of which they are com- 

 posed are embedded in a matrix of silicious cement, or of 

 hard clay, and the formation is found in strips and sheets, 

 flooring our leads and valleys, capping our hills, and terracing 

 our mountains : and they sometimes stream across country, 

 traversing the gullies and ranges, regardless of the levels or 

 of the drainage lines. 



These conglomerates are generally believed to be the 

 remnants of ancient and deserted river beds. We are told 

 that the streams which deposited them have since shrunk 

 into trickling rivulets, and that, meanwhile, their courses 

 have shifted from time to time, until, at last, they for ever 

 left their old beds, although we now know, on the best 

 authority, that the river system of a country is even more 

 ancient, more permanent, more indelible, than its mountain 

 system (" Rivers and River Gorges," A. Geikie, in Eng. III. 

 Mag., Jan., 1884). That as they shifted about they left 

 behind therm, as well as above, these ancient, stone-paved 

 beds, winding about aimlessly and crossing older tracks, 

 until the geological map which records them is covered 

 with a network of lines. TTe are told, also, that the 

 denudation which this country has undergone is very great 

 in amount, and that it has entirely changed the aspect of 

 hill and vale, so much so that we find, here and there, old 

 river beds running along the backs of spurs, as is the case at 

 Cobungra. 



This explanation, although it contains many truths, does 

 not seem, to me, to be entirely satisfactory : and the more 

 carefully I examine the boulder washes the less do I feel 

 disposed to acquiesce in it. 



The facts which are not explained by the fluvial theory 

 may be briefly stated. 



