272 Charles Fenner : 



On the south, a deep tributary comes in from the pat^h of bed- 

 rock here exposed at the surface. This tributary, with its steep 

 and densely timbered slopes, also provides some fine scenery, especi- 

 ally by contrast with the flat, uninteresting plains above. When 

 the river emerges from the Ordovician, we come to the '' mouth " 

 of the Gorge, and in the softer rocks hereabout — mainly tertiary 

 and decomposed older volcanics — the valley is wider and the land 

 of greater economic value. A view near this point is shown in Fig. 

 26. The gentler slopes are lightly timbered, and rich river flats 

 make their appearance. Past the residual basalt-capped; Trig Hill, 

 the Korkuperrimul Creek enters in a wide valley from the north, 

 at a grade quite harmonious with that of the parent stream. 



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Mr. COTTERfLL. 



Fig. 26. — Sketch, looking east, of the view from the hills on the 

 right bank of the Werribee River, below the Gorge. N.B. — 

 Newer Basalts: Tert. — Tertiary sandstones, etc.; O.B. — Older 

 Basalts; P.C. — Pernio Carboniferous sandstones, etc. 



We here pass the line of the Rowsley fault, and a small let-down 

 tongue of lava crosses the river coming from Bald Hill. This 

 causes a narrowing of the valley (see Fig. 38). Beyond that the 

 river valley widens out into the fertile flats of the Bachus Marsh 

 basin, through the alluvial of which it runs in a channel 10-20 feet 

 deep. As is usual with such flood plain deposits, the levels of the 

 '* flats " slope away from the river for some little distance. 



The structure and origin of this basin is discussed later. To- 

 wards the further end of this area, the Parwan enters from the 

 south, and the Lerderderg River from the north, with the Pyrete 

 Creek coming in from the north a quarter of a mile further on. 

 The Werribee then leaves the flats, and swerves to the south, enter- 

 ing once more a young, narrow valley cut into the basalts (see 

 Fig. 38). From this point onward the river flows generally south- 

 east, across the plains, to the sea. A little over two miles along 



I 



