Physiography of Werribee Area. 241 



The writer, travelling a good deal over the country south of 

 Ballarat, has been struck by the dominance of north-south Ordo- 

 vician ridges rising above the newer basalt sheet. The important 

 and isolated Ordovician heights of Mt. Doran, Mt. Egerton, and 

 Haydon's Hill — giving a line sixteen miles long running a few 

 degrees east of north, has already suggested itself to various 

 observers as a relic of the eastern up-tilted edge of a fault block. 

 Thy physiographic evidence seen in frequent cross-country traverses 

 in that area, backed by the contours shown in the field notes of 

 the Commonwealth Military Survey, point towards this line mark- 

 ing a fault, parallel with those of the western highlands, as demon- 

 strated by T. S. Hart (ref. 22). 



(vi.) The Sunklands. — Little remains to be said concerning the 

 great relatively sunken blocks of the Werribee area, which have 

 already been frequently referred to. They are : — 



(a) The Port Phillip Sunkland. 



(b) The Ballan Sunkland. 



(a) The Port Phillip Sunkland. — This has been referred to 

 mainly as block E, though it of course extends beyond that block, 

 embracing Port Phillip Bay. The northern limits of this area have 

 not been investigated, except along the base of the Gisborne high- 

 lands, but the east and west limits are the Rowsley and the Selwyn 

 Faults respectively. This relatively sunken block has given Vic- 

 toria her two chief harbours, the sites of her early settlements, and 

 of the capital city. The known limits are set out in plan in Fig. 5 

 and a section drawn from the 50 foot contours of the Military 

 Survey is shown in Fig. 12, with the geological structure also 

 marked in. The economic aspects have been already referred to 

 under the heading of general description of the area. 



MOORABOOL RIVER. 

 ME«eOITH]sujHeRUN0S^^^^^^ 



l2C>0'HjBs=r->c4x5i^r^--^ 1 WERRlBtt pORT PHILLIP BAY 



I 



TERTIARY RESTING ON ORDOVICIAN, JURASSIC. ET9- 



MfiaiTrtNTi.! SCALE' 5 "J MlLta. ^^ E3 Hla CiiJ . . — . 



HORIZONTAL 5CALL. ?,.,,,,,,., Ordovician. Granife. Jorassic. Newer Rec«nr.4c 



Volcanic. 



Fig. 12.— Section across the Port Phillip Sunkland, from Meredith 

 to Mount Eliza, showing geology and relief. 



The section (Fig. 12) is drawn from Meredith, east to the town 

 of Werribee, and then south-easterly to Mt. Eliza. It will be seen 

 that the sunken portion slopes gently from west to east, the eastern 

 portion, Port Phillip, being below sea level. The depths of the 



