308 Charles Fenner : 



tains, running north and south, were built up. Such evidence lies- 

 in the intense folding along north-south axes which is associated 

 with the extensive (?) Devonian plutonic intrusions, following 

 similar lines, as shown in Fig. 17. It is of further interest to note 

 that the known relics of the earlier upper palaeozoic physiography, 

 buried under the permo-carboniferous glacial deposits, bear 

 witness to north-south valleys. The possibility of lower carboni- 

 ferous sedimentation in this area has been discussed in Section 

 VII. (a). 



The glacial period was itself an erosive period, but its completioa 

 left great masses of morainic material that have been protective 

 of the underlying surfaces, and thus we have preserved in this 

 area relics of the extremely ancient upper palaeozoic landscape, 

 where these valleys have been exposed in section by the present-day 

 streams. 



Examples of interglacial pavements (?) were discovered by the 

 writer in the glacial material at the mouth of the Lerderderg 

 gorge (left bank). Probably the post-glacial " lake " deposits (Fig. 

 39) should be higher up in the column. (Chapman, " Australian 

 Fossils,'' p. 88.) 



The " great erosion period " tlien continued, with what inter- 

 ruptions we know not, right up to the lower-to-middle tertiary 

 period, when the '' Great Peneplain " was completed, and then 

 partly destroyed by the older volcanic flows, with uplift and fault- 

 ing. To this period belong the Greendale fault (post-older and pre- 

 newer basalt), and the other dominant lines of differential displace- 

 ment of this area that have been associated therewith. The northern 

 boundary of the basin of Jurassic sedimentation probably lay to the 

 south of our area. 



Another period of erosion extended to pre-newer volcanic times, 

 the resulting physiography of which, in this area, is largely pre- 

 served below the newer basalts, as shown by the reconstructed river 

 systems in Fig. 35. 



The widespread tertiary series of the Bacchus Marsh area are less 

 than 1000 feet in depth, and may be associated with the accumu- 

 lation of fluviatile material on the lower levels of the penej^lain 

 subsequent to the first great tertiary uplift. Three periods of ter- 

 tiary marine invasion are also suggested in Fig. 39, but none of 

 these affected the Werribee area as a whole. 



In placing the various happenings of the tertiary period in 

 the *' chronological column/' it is not intended to refer them 

 exactly to any particular division of the tertiary period. It will 



I 



