Yarra Improvement Sections. 43 



breadth, and -^^ inch in thickness. No quartz was noticed in the 

 material examined. This dyke is probably identical with that 

 from which the micaceous material in the Anderson Street 

 cutting was obtained, and belongs to the same series of intrusions 

 as the smaller dyke near the old pumping station mentioned in 

 the previous paper, and those revealed^ by the sewerage works in 

 South Yarra.— 7.vi.02]. 



The evidence furnished by the shell-bearing dark clay by its 

 occurrence above the basalt, settles the question of the relative 

 positions of the volcanic and younger sedimentary rocks here. 

 From the evidence of the deposits of sandy clays, sands and 

 gravels, beneath the basalt in tlie Richmond and Clifton Hill 

 quarries the basalt in those places has not flowed immediately 

 over the marine marls, and it is very doubtful if this arm of the 

 estuary ever extended up the valley to the latter place. 



[Dr. Coates records'-^ the occurrence of marine shells Foraminifera 

 and Diatomaceae from "the mud of a swamp near the Yarra, 

 where the iMelbourne and suburban railway crosses that river." 

 He says, that in some of tlie specimens of the deposit " marine 

 shells, pieces of cuttle fish bone, and the debris of echini" occur. 

 Also, that "from inquiries that have been instituted, it is 

 estimated that the swamp has a depth of not less than 60 feet." 

 He was, therefore, of the opinion that the waters of Port Phillip, 

 at a time probably not very remote, covered this locality, and 

 that after elevation of the land took place a lagoon or saltwater 

 marsh was formed, and with further elevation a possible 

 incoming of fresh water destroyed the organisms. 



Accepting this record of marine fossils at South Yarra, the 

 extension of the estuary deposits considerably further up the 

 valley of the Yarra than Anderson Street bridge is clearly 

 proved. The question, therefore, of the relation of the basalt to 

 the shelly marls becomes a still more interesting one. It seems 

 quite improbable for the latter to overlie the basalt, and the only 

 alternatives are either that the basalt is of younger or of 



1 T. S. Hall, M.A., and G. B. Pritchard : A Contribution to our Knowledge of the 

 Tertiaries in the Neighbourhood of Melbourne — Footnote p. 226, Proc. Roy. Soc. Victoria,, 

 vol. ix., n.s., 1896. 



2 John Coates, M.R.C.S.L. : On a Deposit of Diatomaceae at South Yarra — Trans. Roy. 

 Soc. Victoria, vol. v., 1860. 



