PRESIDENTS ADDRESS. 579 



subaqueous tuffs and lavas of an acidic character, the series, about 

 3000 feet in thickness, being strongly unconformable to the Upper 

 Silurian Series, and the eruptions being probably consequent on 

 the prolonged subsidence, during whicli the 35,000 feet of Silu- 

 rian (Upper and Lower) sedimeats were laid down in Victoria. 

 Erosion and subsidence followed, to the amount of 4000 feet in 

 places, considerably reducing the land area in Eastern Victoria. 

 Felsitic and basic eruptions on a progressively diminishing scale 

 upwards prove that the great chain of meridional volcanoes which 

 produced the Snowy River Porphyries was becoming moribund 

 and eventually became extinct long before the Buchan and Bindi 

 limestones, with their i-eraains of bony-})lated fish, were deposited 

 in the eroded hollows of the volcanic series. 



Tn New South Wales also about Middle Devonian time there 

 was probably considerable subsidence, the Coodra Vale limestones 

 with fossil Coccostean fish being now over 1000 feet above sea- 

 level. 



In Queensland during prolonged subsidence over 20,000 feet of 

 strata accumulated, of which at least half, perhaps the whole, are 

 Middle Devonian, the Fanning limestone alone having a thickness 

 of 7000 feet, and being chiefly formed of corals and corallines. 

 The first evidence of a contemporaneous land flora in Australasia 

 is afforded by the plant DiGranojihylluin avstrnlicum, Dawson, of 

 the Queensland Middle Devonian Series. The abundant suncracks 

 in the sandstones also prove contemporaneous land areas in 

 Queensland, though the prolonged sul)sidence must have much 

 restricted the land area in the Burdekin and Fanning River 

 Districts. Contemporaneous volcanic eruptions are evidenced by 

 interbedded tuffs. 



In the Kimberley District of West Australia the conglomerates 

 in the Devonian Series imply neighbouring land areas, and there 

 is evidence (f. Hardman) of extensive contemporaneous basaltic 

 eruptions, the basalt sheet being over 1000 feet thick. Ati^ypa 

 reticularis, Rliynchonella pugniis, an Orthoceras, and two species of 

 Goniatites are recorded from these beds at Kimberley.* 



* Annual General Report for 1890, by H. P. Woodward. By authority. 

 Perth, 1891. p. 17. 



