FhysiograpJty of Varra, etc. 513 



A valley, t'oriiiint^ part of the Croydon Senkungsfeld, stretches 

 from the Yarra, throu<rh Croydon, Dandenong, the Carruin 

 Swamp, and probably under the waters of Port Phillip Bay, 

 as far as Dromana. 



Tlie composite nature and the growth of the Yarra are in- 

 dicated. 



Tlie intluence of the great masses of acid igneous rocks in 

 the evolution of the topography is discussed, and a comparison 

 made between the Upper Goulburn and Yarra Basins. 



Gardiner's and Main Creeks are referred to, and the possi- 

 bility of originally being di.stitict streams with their subsequent 

 history is referred to. 



Some monadnocks and view-points are described, and the 

 possibility of peneplains older than the Nillumbik Peneplain 

 is suggested. 



The existence of rapids and small islands in the Warrandyte 

 Gorge is noticed, and their relations stated. 



An example of differential pot-hole erosion is given. 



A list of the literature referred to is tabulated. 



In conclusion, I desire to thank Prof. Skeats, Mr. F. Chap- 

 man, Dr. T. S. Hall and Mr. Griffith Taylor (now of the British 

 Antarctic Expedition), for advice and helpful discussion on 

 various points connected with this paper. 



Literature. 



1. Gregory, J. W. — The Geography of Victoria. Melbourne, 



1903. 



2. Idem. — The Geology of Mount Ma<::edon, Victoria. Proc. 



Roy. Soc, Victoria. Vol. XIV. (New Series), Part II., 

 1902, pp. 185-217, 7 pis. 



3. Skeats, E. W. — The Volcanic Rocks of Victoria. Pres. 



Add., Sec. C, Aust. Assoc. Advc. Science, Brisbane, 

 1909, pp. 173-229, 3 pis. and map. 



4. Barnard, P. G. A. — In the Valley of the Upper Yarra. 



Victorian Naturalist, Vol. XXIIL, 1907, pp. 245-252. 



5. Hall, T. S.— Victorian Hill and Dale, Melbourne, 1909. 



6. Jutson, J. T. — A Contribution to the Physical History 



of the Plenty River ; and of Anderson's Creek, Warran- 



19 



