Llinhwrgite Rock. 133 



kalimnan fluviatile denudation ; or that it had already reached 

 the original surface of the peneplain as a vent, and was subse- 

 quently planed down along with the bedrock. The former 

 hypothesis is the more tenable, as the lava, being so tenacious, 

 would, if extruded to the surface, have tended to weather out 

 and stand considerably above the comparatively soft bedrock, 

 and thus indicated its differential structure by the formation of 

 a monadnook. 



That this occurrence of lava in so isolated a spot may be 

 directly connected with crust al folding prior to the formation of 

 the Yarra or Nillumibik peneplain, is suggested by the fact that 

 it occurs on the Templestowe anticline of Jutsoni (see text 

 figure), and directed, in its major axis, with the same line of 

 strike as that of the quartz reefs containing antimony and gold 

 at Templestowe. The nearest occurrences of the older basalt on 

 either side of Balwyn are at Lilydale on the east, where there is 

 a vent represented by tuff and cinder cones ; and Flemington, on 

 the west, represented by a rather massive flow of spheroidal 

 basalt.2 The Lilydale volcanic series is situated close to the 

 fault boundary of the Croydon senkungsfeld, which may be 

 directly connected with that remarkable series of tuffs and 



Analyses of Woodend, Bendigo axd Balwyn Rocks. 



1. Proc. Roy. Soc. Victoria, vol. xxiii., n.s., pt. 2, (1911), p. 522. 



2 Note — In the discussion following the reading of the present paper, Prof. Skeats 

 remarked on the interesting discovery of a similar monchiqnite rock occurring as a dyke in 

 *he closely associated VVarrandyte anticline. (See Jutson, Proc. Roy. Soc. Victoria, vol. 

 xxiii., pt. ii., 1011, p. 528). 



