32 Coast Line Formation of the Western District. 



the more solid matters held in suspension far from the mouth 

 of the river. 



Such a formation and the agencies which I conjecture to be 

 in operation are very similar to those of earher times, when 

 the second line of ridge was formed enclosing the Tower Hill 

 marsh and the outer line which encloses the lagoon and flats 

 between the existing dunes and the second ridge ; namely, a 

 heavy sea on the coast breaking down and carrying back 

 with its recoil particles of the coast held in mechanical 

 suspension across a deep water channel, until the under 

 draft meeting with a resistance of force sufficient to check 

 its current precipitates the solids in a long ridge, which from 

 continuous accumulations becomes at last a shoal enclosing 

 a basin ; and in time the shoal emerges as a bank, alter- 

 nately dry and wet, on which the wind can act, and then 

 begins the process of accumulation in ridges and the filling 

 in of the basin with vegetable deposits and growth until dry 

 land appears. 



In one place at Warrnambool the wave action from some 

 cause has become destructive, as evinced by the erosion of 

 the shell limestone, undermining it, and breaking down the 

 fallen materials. The outlyers of these rocks now form 

 dangerous reefs over which the sea breaks for about half 

 a mile seaward of the coast line of the dunes. From what 

 has fallen under my own observation, however, I believe the 

 wave action along the Victorian coast is chiefly conservative, 

 as a proof of which the long ninety-mile beach of Gippsland 

 is an excellent example ; the dunes of Gippsland bear evi- 

 dence of formation from similar causes to those suggested as 

 having been active on the western coast. 



Of the long continuance of the climatic conditions existent 

 in Yictoria the out-throw from Tower Hill afibrds very strik- 

 ing evidence in the great prevalence of its products to the 

 east and south-east of the mount, a direction which would 

 be taken now by ejected matter in any time of great atmo- 

 spheric disturbance. 



The crater of Tower Hill is from five to six miles in cir- 

 cumference, and rises in places to 320 feet above the level of 

 the lake, which occupies a large portion of its area, whilst 

 the island from which it appears to have received its name 

 rises a little higher in mounds and peaks, with one well- 

 defined crater and the broken remains of others. When in its 

 early times of activity, the crater must have been a yawning 



