384 PROCEEDINGS OP SECTION E. 



TERTIARY. 



MIOCENE. 



The oldest members of the Tertiary series occurring in the 

 Australian Alps, are certain beds of auriferous gravels, clay, 

 sands, fine gravels, ferruginous or siliceous conglomerates, and 

 lignites containing leaves of Miocene age. The leaves are found 

 in a yellowish-brown laminar clay^ and have been identified and 

 named by Professor McCoy as Lastrea dargoensis, Tceniopteris 

 tenuissirne-striata, Cinnamoinum, polymorphoides^ and Saiisburia 

 Murrayi. These Miocene river gravels are overlain by sheets of 

 basalt, as on the Dargo and Bogong High Plains.* The present 

 river valleys have been eroded along the margins, and in some 

 places across the lava flows to a depth of, in some places, over 

 one thousand feet, as on the Dargo at Mayford. Fine escarpments 

 shewing columnar basalts are seen along the edge of several of 

 these plateaux. The lava would appear to have welled up through 

 fissures, as no localities have yet been found where volcanic vents 

 occur. From the examination of the Dargo High Plains area, 

 the basaltic sheet is not less than seven hundred to eight hundred 

 feet thick in places. The localities where such basaltic sheets 

 occur, are Bogong High Plains, 6,000 feet ; Dargo High Plains, 

 5,000 feet; Gibbo Table-land, 3,000 feet;t Nuninyong Table-land 

 4,000 feet ;| Gelantipy Tableland, 4,000 feet. 



PLIOCENE. 



The Pliocene fluvatile deposits are represented by terrace 

 deposits in the mountain valleys, and deep leads at the lower 

 levels — generally made up of heavy boulder and gravel deposits, 

 clays, and sands, mostly auriferous. 



These deposits have evidently suff'ered extensive erosion, and 

 the removal of some of the huge boulders to long distances is 

 strongly suggestive of glacier translocation. 



The localities where such terraceous deposits occur are as 

 follows : — In the Ovens Valley, above Bright ; Mitta Valley, 

 near Omeo, and on the Big River ; Kiewa River, at Mountain 

 Creek ; Hume Rivei', above Groggin ; Tambo River, near Little 

 River Junction ; Snowy River, above Turnback ; Mitchell River, 

 on the hills east of Dargo Flats ; along the upper courses of the 

 Wongungarra and Wonnangatta. With the exception of an 

 abundance of silicitied wood, apparently of a species of Eucalyptus, 

 in the terraceous deposits, I am not aware that any fossils have 

 been found. 



* R. A. F. Murray, Progress Report, Geol. Survey. Victoria. No. 5, pp. 96-101 . 

 ^Vide Geoloffical Traverse of the Mitta, by J. Stirling, Reports Mining Registrars, 'V'ic. 

 toria, December, 1887. 

 I Physiography of the Tanibo Valley, by J. Stirling. Trans. Geol. Soc, Australasia, 1888. 



