[Proc. Rov. Soo. ViCTOKiA, 26 (N.S.), I'T. I., una.] 



Akt. III. — On the Age <in<l PhyxKHjKtph'ic Relatione of the 

 Older Basalts of Gremsboruagh and Kangaroo Ground^ 

 and of certain Basalts at Bundoora and Ivanh,oe. 



Bv J. T. JUTSON 



(Geological Suivey of Western Australia). 



[Kead i. th April. 1913J. 



Introduction and Previous Literature. 



The Kainozoic basalts of Victoria have hitherto been divided intO' 

 two main series, the Older Basalt and the Newer Basalt. The 

 tornier is represented by the isolated patches lying mainly to the 

 east of Melbourne, and the latter by the great volcanic plains tO' 

 the west of the same city. 



Whilst, however, these two principal series have been recognised, 

 some suggestions have from time to time been made that there is an 

 intermediate series. Thus, as pointed out by Mr. T. S. Hart in his 

 '■ Volcanic Rocks of the Melbourne District,"! the older volcanic- 

 rocks are divided into two groups on the Geological Survey Maps — 

 viz.. Older Volcanic and Lower New Volcanic. Mr. Hart shows that 

 the largest aiea of the Older Basalts, near Melbourne, lies along 

 and to the east of the Saltwater- River, and reaches down to Mel- 

 bourne, reappearing beyond the Yarra at Emerald Hill; and that 

 the greater part of it is coloured and lettered on the maps as Older 

 \ olcanic. the south-eastern end is coloured and lettered as Lower 

 .New Volcanic, and the middle is coloured Lower New Volcanic and 

 lettered Older Volcanic. Mr. Hart concludes that from the sections 

 round Melbourne there is a series of older volcanic rocks, overlaid 

 by marine Tertiaries, and perhaps a second series before the newer 

 volcanic. Mr. Hart also discusses the age of the Greensborougli 

 older series of basalts, as will be shown later. 



Messrs. Hall and Pritchard in their paper on the Tertiaries in 

 the neighbourhood of Melbourne2 also point out (p. 189) that the 

 volcanic rock at South Melbourne and West Melbourne is coloured 

 on the Geological Survey Quarter Sheets as Lower Volcanic — i.e., 

 Lower Newer Volcanic — and is so lettered except on Quarter Sheet 



1 Vict. Nat., vol. .\i. (1894), p. 75. 



2 I'roc. Roy. Soe. Victoria, vol. ix. (N.S.), 1?<96, pp. 187 •2-29, pi. 8. 



