[Peoc. Roy. Soc. Victoria, 22 (N.S.), Pt. II., 1909.] 



Ar'I'. XII. — .4 Contribution to the Fltysical History 

 of the Plenty River; and of Andersons 

 Creek, Warrandyte, Victoria. 



By J. T. JUTSON. 



(Victorian Government Research Scholar). 



(Plates XXXI-XXXir., and two Text Figures). 

 [Read 11th November, 1909]. 



THE PLENTY RIVER. 



Description of the Valley. 



This river rises in Mount Disappointment, and runs prac- 

 tically due south until it meets the Yarra to the west of 

 Templestowe. Its basin was geologically surveyed by the old 

 Geological Survey of Victoria, and the geology is accurately 

 delineated on Quarter Sheets 3 N.E.. 3 S.E., 2 N.E., 2 S.E., 

 and 1 N.E. In its course from source to mouth, the river 

 passes through granitic, basaltic and sedimentary silurian and 

 tertiary rocks. In the granitic area of Mount Disappointment, 

 the eastern and western branches are each split up into a 

 number of small streams, which, upon reaching the silurian 

 country, soon imite to form the two branches mentioned. 

 Bruce's Creek, which joins the Plenty at Whittlesea from the 

 north-west, is its largest tributary, and is, in fact, the main 

 sti-eaiii. 



The character of the valley of the Plenty immediately in- 

 vites investigation. In the neighbourhood of Whittlesea, the 

 stream is sluggish, shallow and meandering. It runs through 

 itj own alluvial flood-plain (which in places is a mile wide), 

 bounded by subdued hills ; and, with its tributaries, presents 

 all the features of a matured river system. Below the Van 

 Yean Reservoir the Plenty meets the newer basalt, through 



