216 Charles Fenner : 



lava flaws, and well marked in the boundary of the Ordovicians 

 rocks south, of Rowsley." 



The same writer (ref. 22, p. 26), believes that, at a point east of 

 Trig Hill, Bacchus Marsh, " there is a monocline probably faulted, 

 and further south along the edge of the high basaltic plateau, a 

 fault scarp over which the lavas have flowed." He refers to its 

 southern continuation, as indicated for about six miles on Quarter 

 Sheet 12 S.E., and states : "As the line of fault passes between the- 

 old township of Rowsley, and the railway station of the same name, 

 I will call it the Rowsley fault." 



In a map of the " Tectonic Features of Australia and Tas- 

 mania," accompanying Professor David's article on tlie Geology of 

 the Commonwealth (ref. 12), there is a large E.W. fault shown, 

 with a down-throw to the South; it is labelled ''Bacchus Marsh 

 Fault," and is evidently intended to indicate the northern boun- 

 dary of the " Great Valley of Victoria." The Bacchus Marsh 

 scarp, however, really runs almost north and south (see Fig. 5), 

 and the series of E.W. faults that probably bound the " Great 

 Valley " yet remain to be investigated. 



Wilkinson and Daintree (ref. 56), in the sheet of notes attached 

 to Quarter Sheet 12 N.E., refer to the scarp at Bacchus Marsh, 

 and say : — '* A similar feature must have existed in the Miocene 

 formations i3rior to the flow of newer basalt, which has evidently 

 flowed over a steep face 200 feet in height." The origin of the 

 scarp is not discussed. 



Professor Skeats (ref. 47, p. 208) also mentions this scarp, and 

 says : — " It may be formed by denudation or may represent a fault 

 scarp formed during the eruptive period." 



Andrews (ref. 1, p. 477) refers to the " Bacchus Marsh Fault" 

 as one of uplift, and adds: ''Not yet examined carefully. It is 

 a dismantled scarp to the north of Bacchus Marsh. Some of the 

 associated basalts are older and some younger than the scarp." 



The writer has carefully examined this scarp along nearly the 

 whole thirty miles of its length, and has been greatly aided by the 

 geological survey maps of the area, coupled with the contour maps 

 of the Military Survey. He must confess to a regret that he was 

 unable to examine the scarp with closer detail in the immediate 

 neighbourhood of the Anakies, and in the few miles of more inac- 

 cessible country in the extreme north. He is confident, however, 

 that such examination would only furthet- confirm the results al- 

 ready arrived at. 



