360 Afoi-rts Morris: 



consider wliether. although it be the reverse of wiiat Mr. Jutson 

 pustuhited. it may not. as he believes, bv a northern continuation, 

 of Selwyn's fault. If it may, then we must imagine a see-saw 

 movement on an east and west axis, south of which, if the beds 

 Were depressed, then north of it they must have been elevated, and 

 vice-versa. 



Now, this see-saw movement could have occurred on the east of 

 the fault pane, or on the west of it. It did not occur on the west 

 of it, for the senkungsfelder iii the north, and the Carrum Swamp 

 in the south, indicate a depression at both ends of the block. It 

 can only have occurred, therefore, if it occurred at all, on the 

 east of it, the sinking of the Dandenongs in the north being 

 balanced in the south by a rising of the granitic areas of Morn- 

 ington peninsula. 



The presence of the small l>asalt-capped plateau lying west of 

 Cave Hill, Lilydale, suggests the possibility of its being the eastern 

 boundary of the Croydon Senkungsfeld. In this case, if the bound- 

 ary were determined by a fault, that fault would lie one and a half 

 or two miles west of the Montrose fault. 



T/ie Olinda Fault. — It has already been noted that where the 

 Evelyn fault meets Olinda Creek, it appeals to have l)een heaved 

 out of its course about 250 yards to the east, with the result that 

 the series d is noAv found at the foot of the high clifis of hornfels 

 and series c on the north bank of Olinda Creek, which occupies 

 the junction. (Plate XXX., Fig. 4.) The existence of this Olinda 

 fault is supported by all the evidence in favour of the Evelyn fault. 

 If, therefore, the latter be taken as established, the former must be 

 also. The downthrow was on the mountain side, where the igneous 

 rocks are preserved against the silurians. 



Above the Evelyn fault, the Olinda Cieek valley is veiy young. 

 It is marked by rapids and waterfalls, the latter having receded 

 more than one mile above the fault, lielow the fault the valley 

 widens, so that the stream meanders through wide alluvial flats. 

 This rejuvenation of the stream has probably resulted in its cap- 

 turing much of the headwaters of Stringy Baik Creek. 



VI, — The Tertiary Igneous System. 



I have taken Stirling's boundaries for the t)asalt. The basalt 

 lies upon the silurians, capping a small plateau west of the railway 

 line, between Lilydale and Mooroolbark. At Cave Hill it occupies 

 an old river channel, whose sands lie between it and the limestone. 



