Ya7'ra Imjyrovement Sections. 45- 



In a recent paper^ by Mr. J. F. Mulder, the basalt of the 

 plains of the Moorabool River, near the viaduct on the Geelong- 

 Ballarat Railway, is shown to be resting upon a deposit of sandy 

 gravel, full of calcareous casts of Newer Pliocene fossil shells, thus 

 proving the basalt to be not older than Newer Pliocene age. The 

 upper volcanic rocks of the whole of the Western Plains coming 

 eastwards to the Melbourne district are regarded as belonging to 

 the one age. Therefore, the basalt in the Lower Yarra Valley 

 must be Newer Pliocene or younger. 



Evidence is present showing that the whole of the area 

 bounding the Yarra Estuary was within late geological time 

 beneath the waters of the Bay, and has since been slowly raised. 

 Meanwhile the Yarra continued cutting its channel deeper, 

 and extending its mouth till at the present time this is about 

 5 miles away in a straight line from its former mouth at the 

 Botanical Gardens. 



The occurrence of indentations in the eastern shores of Port 

 PhillijD, such as the areas occupied by the Elwood and Carrum 

 Swamps, and the thin deposits containing recent shells which 

 cover a large extent of the coast along the western shores of Port 

 Phillip from Williamstown towards Geelong, also prove that the 

 area bordering the northern part of Port Phillip is one of 

 comparatively recent elevation. 



Again, along the margin of Western Port, and in the valley of the 

 Powlett River in South Gippsland, there also occurs what seenis 

 undoubted evidence of the existence oi a large sheet of water in 

 comparatively recent times, and of subsequent elevation of the land 

 surface. In the Powlett Valley the country in some parts has 

 the appearance of an area originally consisting of low mud banks, 

 islands and promontories, separated by indentations with fairly 

 deep channels having the character of those now visible in 

 Western Port. [Further east, also, such as along the northern 

 shores of Corner Inlet, evidence of elevation does not seem to be 

 wanting. It seems, therefore, as if a considerable portion of the 

 southern coast of Victoria has undergone some elevation during 

 recent times. I am indebted to Messrs. T. S. Hall, M.A., 



1 J. F. Mulder : Newer Pliocene Strata on the Moorabool Hiver — Proc. Roy. Soo. 

 Victoria, vol. xiv., part ii., 1901. 



