130 Excursion to Yering Gorge. [voKXXxi. 



since it lies in practically the same line of strike. In other 

 words, it forms a continuation of the gentle fold-trough of 

 the Lilydale series of Silurian rocks, typical of the upper or 

 Yeringian scries. Since the rock in this part of th^ country 

 is a comparatively soft mudstone, the lateral erosion of the 

 drainag(> system gave rise to the ' flat-land,' a true paradise 

 for the ' jiond-lifer.' Striking the river valley, we met the head 

 of the Gorge, which here is one-sided, or bounded on the. north- 

 west by elevated river-cliffs and on the south-east or le'ft bank 

 by the flat-land. Proceeding down the river, the cliffs on the 

 opposite or Christmas Hills side became at times precipitous, 

 and often of great elevation, probably as much as 250 feet 

 above the river. This part of the Yarra has been namdd the 

 Yering Gorge by Mr. J. T. Jutson, and those interested in the 

 physiography of these parts would do well to consult his 

 description of it in the Proc. Roy. Society Vict. (vol. xxiii., n.s., 

 part 2, 191 1, p. 484 et seq.) A curious feature of the Gorge 

 has been pointed out by Mr. Jutson — namely, the bold turns 

 which it makes, which one would hardly expect if the stream 

 were rejuvenated, or increased in erosive power, by a com- 

 paratively sudden uplift. Jutson's explanation of this is that 

 ' the elevation was fast enough to allow continuous vertical 

 erosion, but at the same time slow enough to permit the river 

 to curve extensively.' The course of the Yarra in this part 

 has undoubtedly been determined by a fault or crustal move- 

 ment in a vertical direction and following the line of strike. 

 Hence we have on the right bank a precipitous cliff of hard 

 sandstone rocks of the Warrandyte series, and on the left bank 

 in some places flats with little swampy gardens of mosses and 

 liverworts, in others a comparatively low river cliff of hard 

 rock, although not so steep as on the opposite side of the 

 river. According to Mr. Jutson, the hard rocks on the right 

 bank of the river appear to belong to an older series, probably 

 of the Melbournian grouj). This difference of geological 

 horiz(jns on the oi)posite banks can be easily explained l)y the 

 evidence of great vertical upthrow of the rocks forming the 

 Yering Gorge. Had there been no uplift at all on the ' down- 

 throw ' side of parts of the Gorge bounded by flats and ridges, 

 the district from Yering to Croydon would have become, as 

 pointed out by Jutson, a great lake, until drained through at 

 the lowest ])oint of the basin. In this neiglil)ourlu)0(.] is the 

 valley of the Brushy Creek, with its tortuous course over the 

 flat-land, and this, together with the fossiliferous and other 

 quarries, would be well worth visiting on a future occasion." 



After gutting through the hilly country, we rested for a while 

 at a shady spot on the river, and had afternoon tea. A turn 

 was then made southwards towards Lilydale, some six miles 



