Physiographji of Yarra, etc. 479 



between a fairly hard and a softer band, following the strike 

 of the rocks. It may here be stated that the difference in 

 hardness between the rock-bands mentioned is (luite insufficient 

 to account for the existing- topography. 



South of the Dandenong Creek, the lirushy Creek Fault can- 

 not be traced. If, however, a line be drawn south-westerly in 

 continuation of the fault to about Spring-^^ale, it will be seen 

 that while the general level of the country along this line 

 gradually descends to the south, it also appears to steadily 

 drop to the east, until th6 low ridges and flats of Bayswater 

 and Scoresby are met with. Thus the fault seems to die out 

 and become replaced by a gentle tilting approaching a slight 

 fold. This idea is supported by the decreasing throw of the 

 fault when traversed from north to south. 



Tlie second fault, which may be referred to as the Yarra 

 Fault, runs north-easterly from the northern end of the Brushy 

 Creek Fault to about two miles to the north of the Yarra at 

 Yarra Glen. It constitutes a boundary of the Croydon Sen- 

 kungsfeld. Its length is about nine miles, and it keeps close 

 to and is practically parallel to the Yarra River. It is on the 

 right side of the stream, except as will be noted later. 



This fault also has a very prominent and practically un- 

 broken scarp. 



The difference in height at various points (e.g., at the mouth 

 of Brushy Creek, about 200 feet, at Croydon abut 140 feet, 

 and at the " Kopje " about 85 feet), between the Yarra Plateau 

 and the Croydon Senkungsfeld, indicates approximately the 

 throw of the Brushy Creek Fault, whilst similarly the throw 

 (about 200 feet) of the Yarra Fault is indicated at the Yering 

 Gorge. 



The nature of the other boundaries of the Croydon Sen- 

 kungsfeld have not yet been ascertained, but from casual 

 examination there appears to be a strongly marked but broken 

 scarp running from north of Yarra Glen (a little above the 

 junction of Steel's and Dixon's Creeks), eastward towards 

 Healesville. This scarp is probably due to a fault. Faults on 

 each side of the Yarra north of Killara, one along the edge of 

 Mt. Toole-be-wong, and the other on the eastern side of the 

 Warramate Hills, probably account for the depression here. 



