470 J. T. Jutson: 



In this work Professor Gregory (pp. 106-113) discusses the 

 history of the Yarra Basin, and suggests that most of the 

 principal northern tributaries of the Yarra were originally con- 

 tinuous with the principal streams now flowing northerly to the 

 Goulburn Rive)*, but formerly having a southerly flow : and 

 also that a stream formed by the junction of some of these 

 older larger streams (the Acheron-Watts and the Yea-Steel's 

 Creek) originally passed over a gap at Beenak, and entered 

 Western Port Bay through the Kooweerup Swamp. This of 

 course was when the general surface of the Yarra Basin was at 

 a greater elevation than it is at present. Subsequently the 

 Yarra and Goulburn Rivers worked their way eastward and 

 captured the various streams, dividing them into two portions 

 in some places, and into three in the case of the river which 

 he thought formerly passed over the Beenak Gap, and of 

 course reversing the flow of some of the captured parts. The 

 Yarra. he states, cut its way along an eastern and western val- 

 ley, giiided by the earth movements that succeeded the erup- 

 tions of Dandenong and the Black Spur. These eruptions Pro- 

 fessor Gregory elsewhere (2, pp. 212 and 214) states, were pro- 

 bably post-Palaeozoic, and certainly earlier than the Upper 

 Cainozoic, and might belong to any part of the Mesozoic or 

 Lower Cainozoic. 



The present paper does not discuss the questions here raised 

 by Prof. Gregory, but confines itself mainly to the history of 

 the Yarra and Dandenong Creek since the last great uplift 

 of the land, which, in the writers opinion, occurred after the 

 formation of the peneplain, which is subsequently referred to 

 as the Nillumbik Peneplain. 



Prof. Gregory (1, p. 84) also refers to the Yarra Plateau as 

 the third southern spur of the peneplain running southward 

 from the Primitive Mountain Chain. This peneplain, he states, 

 ran from the Strathbogie Ranges across the present main 

 divide between Mt. Disappointment and Mt. Arnold, form- 

 ing the old platform under the Dandenongs. He further re- 

 marks (p. 85) that most of the Yarra Plateau may be regarded 

 as a shelf on the eastern border of the Melbourne Basin, of 

 which the eastern boundary may then be drawn along the 

 ridge through Queenstown. Christmas Hills and Mooroolbark. 



