170 Frederick Chaponan : 



and therefore Post-Kaliiunaii or Werrikooian, and this conclusion 

 appears to agree with the evidence from Bellevue and the general 

 sections along the Orbost railway line. Moreover, these k)wer 

 sands with echinoids are, ]jrima facie, marine, whilst the torrent 

 gravel by the nature of its composition, as the debris of mountain 

 streams, is undoubtedly of terrestrial origin. 



This term ** terrestrial gravels," was previously used by Dr. T. 

 S. Hall in liis paper quoted, and who refers to its origin as *' a 

 waste-sheet from the mountains to the north, "i If this subaerial 

 origin w^ere doubted, the following points should settle the ques- 

 tion : — 



1. — Were the gravels of marine origin the pebbles would have 

 been of a more uniform size, due to sorting by wave action, and 

 the finer sand carried away. The Bairnsdale gravels consist of 

 large and small boulders and pebbles embedded in fine and coarse 

 sand. 



(Darwin, in describing the gravels of the sloping terraces of the 

 Cordillera, 2 shows how terrestrial gravels of the terraces consist of 

 waterwovn pebbles, angular, subangular, and rounded, and are 

 embedded in fine sand; whilst the lower talus plain, which he con- 

 cludes has been subjected to marine influence, has Avell rounded 

 pebbles interstratified with fine sand. The present writer endorses' 

 these distinctive points from observations made on raised beach 

 deposits both round the British Islands and on the Australian 

 coast.) 



The same physical structure is seen in the case of glacial tills, 

 where sorting by levigation has had no chance to work. 



2. — In a marine beach or littoral deposit, sea-shells, shell-frag- 

 ments or encrusting organisms would almost invariably be present. 

 For example, the gravelly marine beds (Janjukian and Kalimnan) 

 of the Paynesville Bore do contain marine shell-fragments. The 

 Patagonian beach gravels have the pebbles frequently encrusted 

 with marine organisms. 



3. — The presence of silicified (derived) blocks of fossil wood 

 clearly point to a tei-restrial origin, for if drifted wood it must 

 have been silicified subsequently to deposition, yet there is no trace 

 of the siliceous cementation of the bed containing the wood. More- 

 over, all drift w^ood in fossil dep(»sits seen by the writer showed 

 traces of attack by marine organisms as Teredo and worms. 



1 Victorian Naturalist, vol. xxxi., 1914, p. 33. 



2 Darwin. Geol. Observations on the Volcanic Islands and parts of South America, visiteti 

 duriiiff the voyage of H. M.S. Beagle, 2nd ed., 1876, pp. 286-9 and pp. 290-92. 



