158 Robert A. Keble: 



Rtsiduah of the Western Port st/stem. 



The residuals along tlie valley of the main pre-Older Basalt 

 >;treani of the Western Port system, from Mt. Buller to Drouin, 

 have already been mentioned (p. ante). The Drouin lesidual 



has been truncated southwards by a bloek fault. At Lan*,' Lang, 

 .Kouth of Drouin, the basalt is 436 feet below the surface, but it 

 again appears at tlie surface on the mainland at the nortli-east 

 corner of Western Port Bay. From the last mentioned point to 

 .Flinders and Cape Schanck, it probably exists as an unbreached 

 ..sheet. This stream is identical in direction with Prof. Gregoi-y's 

 Tarago, but since the present Tarago is much more recent, and, 

 moreover, is a cros stream, anotlier name would be more appro- 

 pi'iate, and it will be referred t) in future as the Flinders. 



A large tributary of the last mentioned stream had its source 

 .r.omewhere north of the Woori Yallock residual, and was probably 

 identical in its head-waters Avith the Watts, Its course is repre- 

 ;sented by the ** uncovered residual," of Steel's Range, the Woori 

 Yallock residual, the Gembrook residual, the Pakenham residual, 

 -and by a line of conspicuous " uncovered residuals" disappearing 

 into the Koo-wee-rup fault block towards the trunk stream. Above 

 the Gembrook bottle-neck this tributary received a tributary from 

 the north-east ; it originated on the westerly slope of Mt. Donna 

 ]^uang. 



Another large tributary had its source north of the Kinglake 

 <iap and is probably represented in its head-waters by the reversed 

 Yea Ri\er. South of the Kinglake-Gap its course is represented 

 by the uncovered residual between Steel's Creek and tlie parallel 

 valley to the west, and still furthei' to the south, by the Lilydale 

 residual. It then trended southwards through the Lysterfield 

 •Gap below which it is represented by the Hark away, Berwick and 

 Beaconsfield residuals. It joined the trunk sti-eam somewhere in 

 the vicinity of French Island. 



A smaller tributary had its source to the north of Cranbourne, 

 Howed in the vicinity of the Cranbourne residual, and joined the 

 main stream' or a tributary of it in the vicinity of French Island. 



There are many smaller residuals which from their configura- 

 tions, positions and characteristics lead one to believe that they 

 Iiave been developed from infilled tributaries or by cross streams. 



