Physiography of Werribee Area. 215 



The scarp is really about thirty miles long, and is economically 

 .and topographically the most interesting feature of the whole area 

 under discussion. It acts as a barrier between the lower early- 

 settled plains of the low^er Werribee and! the important agricultural 

 and mining centres of Ballan, Ballarat, Blackwood, etc. It pro- 

 sents a. difficult problem to' the engineer, and while the railway has 

 ascended by an extended loop, the climb is still difficult, and extra 

 power is required to carry trains up the stiff rise of 1300 feet from 

 Bacchus Marsh to Ballan. The main road also takes a devious 

 course, along the valley sides, but it, too, still presents sustained 

 and difficult grades to the traveller. 



The following opinions have been advanced regarding this 

 scarp : — 



(i.) Professor J. W. Gregory (ref. 21), in the introductory chap- 

 ter of his Geography of Australia, states : — 



" The high bank to the west of Bacchus Marsh, 1000 feet in 

 lieight, up which the train climbs on the way from Melbourne to 

 Ballarat, is one of the oldest, well-preserved valley walls in the 

 world. It was carved out by river erosion in Silurian times. It 

 was in existence before the materials of which most of the Alps 

 are built had been laid down in the seas of central Europe. It was 

 old before the first bird or mammal or reptile had been born upon 

 the earth, and it dates back earlier than the building of the lands 

 whose foundering formed the Atlantic Ocean. That old valley wall 

 at Bacchus Marsh remained long hidden beneath sheets of sand, 

 gravel and clay, the partial removal of which has once more ren- 

 dered it an important feature in the Australian landscape. It has 

 again been protected by a cascade of molten lava that poured over 

 its edge from the volcanoes of the plateau behind it; and that coat 

 of rock has given a renewed lease of existence to this venerable 

 ■geographical feature. ' ' 



Notwithstanding the literary merit of this account, the fact 

 remains that the structure and materials of which this scarp is 

 built at Bacchus Marsh quite preclude the possibility of its being 

 older than Middle Tertiary. Ancient glacial valleys, to which the 

 Professor's fine description may be applied, are elsewhere exposed in 

 section in this district, as set out by Messrs. Brittlebank, Sweet 

 and David (ref. 7).. 



T. S. Hart (ref. 24), in some notes in the Students' Magazine of 

 the Ballarat School of Mines, of a few years ago, briefly refers to 

 the scarp thus: — '' The edge of the high ground here was probably 

 •determined by a fault scarp not altogether obliterated by newer 



16a 



