Fkysiography of Werrihee Area, 2(38 



(b) Rivtrs and Valleys. 



The Werribee River basin as a whole will first be dealt with, in 

 its relations to the neighbouring river basins; then the Werribee 

 in relation to its own tributaries, and finally a detailed description 

 of each river, concluding with an account of the " buried rivers." 



(i.) The, Werribee Basin and its Divides. — The general relations 

 between the Werribee River and neighbouring streams are set out 

 in Fig. 23. On the lower plains we find the Little River and 

 another small stream (Chen ytree creek) adjoining the Werribee on 

 the south, with a very gentle rise acting as divide between them. 

 In the northern part of the plains the relatively high ground 

 around the volcanic centres of Bald Hill and Spring Hill forms a 

 natural divide between the Werribee and the Balliang Creek, a tri- 

 butary of the Little River. Further seaward this divide is con- 

 tinued in the general rise around Mt. Mary or Green' Hill. Thence 

 to the sea the ordinary gentle irregularities of the volcanic plain 

 have determined the limits of the two basins. 



The southern tributaries of the Parwan have penetrated very 

 Klightly into the Oi"dovician block of the Brisbane Ranges, having 

 found much easier courses in the soft, level-bedded tertiary sands 

 and clays. Here the fault line bounding the southern edge of the 

 Ballan Sunkland practically forms the divide. The Brisbane 

 Ranges are liere drained by headwarter streams of the Little River 

 on the east, and by Eclipse Creek, a tributary of the Moorabool, on 

 the west. The higher ground around Mt. Wallace (volcanic), also 

 helps to form the divide between Eclipse Creek, a tributary of the 

 Moorabool, and Spring Creek, a tributary of the Pai'wan. 



Coming now to the west, the Werribee is bounded in that direc- 

 tion by the basin of the eastern Moorabool. This is a strong, south- 

 flowing river, with a deep young valley cut mainly through the 

 newer volcanic sheet into the Ordovician and other rocks Mow. 

 The boundary (between the Werribee and the Moorabool, is very 

 low. 



Much speculation has been indulged in as to whether the eastern 

 Moorabool originally (in pre-newer volcanic times) flowed into the 

 Werribee, or vice vei'sa, or whether both streams may have been 

 tributaries to a hypothetical ancient Parwan. The area was closely 

 examined for evidences as to this. The point west of Ballan. where 

 the eastern Moorabool takes; a sharp loop eastward, so that only a 

 mile of level country separates the two young channels (Moorabool 

 and Werribee) was specially examined. The Werribee here lies 



I'.U 



