24 THE VICTORIAN NATURALIST. [Vol. XXVI. 



as the shell-beds near the Williamstown racecourse, and see what 

 explanations can be offered that may still be in reasonable agree- 

 ment with the foregoing remarks. Let us take up a position for 

 observations from the grassy bank just above the present beach 

 and look seawards. Even at high tide, with only a crescentic strip 

 of sandy beach a few feet in width below us, the shallowness of 

 the water off this shore can be noticed, but at low tide a very much 

 finer impression can be obtained, and the development of a sand- 

 bank running parallel with the coast is at once seen. There are 

 times when a strong north wind keeps the tide back from 

 properly rising over the sand-bank even at its present height, and 

 it does not therefore require a very great stretch of the imagination 

 to understand the conditions which would ultimately raise the 

 bank to such a level that the high tide would no longer be able 

 to surmount it. Inside the bank there would be a salt-water 

 lagoon, with its collection of dead and living shell-fish and other 

 organisms. This, when once beyond the reach of fresh accessions 

 of sea water, must necessarily gradually soak away or evaporate, 

 and the depression gradually becomes shallower by layer after 

 layer of wind-blown sand. Rain water soon dilutes the saltness 

 to brackishness, and brings about the conditions suitable for the 

 moUuscan genera found in such regions, and enables us to 

 account for the occasional layers of such remains in similar sands 

 to the marine shells. Then plants of the dwarf pig-face type and 

 others capable of existing under salty-soil conditions gradually 

 make their appearance and contribute their share towards the 

 permanent infilling of the lagoon depressions. The old beach 

 slowly becomes sweetened by the continual percolation of rain 

 water, and ultimately supports some of the coarser sand-binding 

 grasses. A perfect sequence of such events as these can be seen 

 if we look towards the Williamstown Racecourse, and a series of 

 grassy and parallel crescentic tracks one behind the other marking 

 the successive sandy beaches can be traced right up to the 

 railway cutting already described. Here, then, there appears to 

 be no necessity to call in elevation of the sea bottom to our aid. 

 except such elevation as would be due to the building up of 

 an extensive accumulation of several feet in thickness on a 

 shallow shelving shore-line by the joint action of wind and tide. 



This reclaiming process is still going on, and along this part of 

 our coast the sea is being slowly pushed back. Such deposits 

 are evidently Recent. The upper i6 feet or so of sands overlying 

 the Pleistocene marine silts of the West Melbourne Swamp area 

 should be regarded as contemporaneous with the Williamstown 

 shell-beds. 



Up to the present there is no evidence for ascribing any of the 

 local aboriginal feeding-grounds to a high antiquity,. and they also 

 must be referred to as Recent. 



