474 J. T. Jutson: 



especially noticable towards the mouth of the Dandenong 

 Creek (where they would be expected), and, where unlooked 

 for. at the head waters of the stream, and its principal tribu- 

 taries. 



The main geological formations may be seen from the map, 

 showing the Yarra and portion of the Goulburn Basins. The 

 main divisions are the silurian sedimentary rocks, the dacite 

 and granodiorite, and the tertiary sands and gravels. The 

 silurian occupies most of the peneplain through which the 

 Yarra runs, as well as forming part of the divides. The grano- 

 diorite and dacite form the highest lands of the area, rising 

 to about 4:000 feet at Mount Donnabuang, near Warbuiton. 

 They are found about the divides. 



The tertiary sands and gravels forming the coastal plain to 

 the east and south-east of Melbourne, are a thin cap on the 

 silurian rocks, and occur in the southern part of the countiy 

 now dealt with. They have in places been much denuded. 



The Yarra Plateau. 



Prof. Gregory's description of the Yarra Plateau has already 

 been quoted. It is proposed to extend the boundaries of this 

 plateau, so as to include country that naturally falls within 

 its area, as well as the coastal plain to the east and south- 

 east of Melbourne. The latter is included for convenience of 

 reference. 



The plateau is bounded on the north by the Main Divide, 

 or by some of the spiu-s of the latter ; and Mount Disappoint- 

 ment may be regarded as the western extremity of its northern 

 boundary. 



The rise from the jjlateau at its northern boundary is sharp. 

 This is noticeable at Mount Disappointment, and particularly 

 80 at Bear's Sugar Loaf, a high, southerly-projecting spur from 

 the Divide. This spur at its southern end is sharply and 

 steeply truncated, which may be due to denudation during the 

 formation of the peneplain, of which the Yarra Plateau forms 

 a part. 



in contrast are the spurs from the Main Divide about Yarra 

 (jlen and Healesville. They are long and sloping, and continue 



