300 Charles Fenner: 



its valley in the hard basalt, the Lerderderg, Werribee, etc., in 

 the neighbourhood of Bacchus Marsh would find time to widen their 

 valley in the softer rocks, and then to meander in that valley, and 

 so to form a " basin." The^ tendency would be to extend the basin 

 down-stream by meanders, etc., undercutting the basalt sheet, 

 which here overlies very soft sands and clays; thus the basin would 

 be enlarged to embrace the junctions with the Parwan and Pyrete 

 Creeks. Most of the work has been done subsequent to the rivers 

 cutting through the basalt into the clays, etc., below. An examina- 

 tion of the limiting eastern wall of the basin, to the south and 

 north of ** Anthony's Hill," assists in confirming this view. 



Remnants of the old apron of alluvium are still to be found in 

 extensive coarse pebbly terraces that occur at different levels all 

 along the western margin of the Bacchus Marsh flats. The soil of 

 these terraces is much poorer and more difficult to irrigate than 

 that of the ''flats." 



A smaller basin, quite similar in nature and origin to the 

 Bacchus Marsh basin, occurs to the west of Bacchus Marsh, at 

 ^' Blink Bonilie " farm.' Here Lyell's Creek (the Korkuperrimul) 

 and the Werribee meet behind a small lava tongue, which they have 

 now quite cut through. The narrowing influence of this tongue 

 of hard rock, with the flats formed in the softer rocks upstream, 

 may be well seen in the field, and is suggested in Fig. 38. 



Bacchus Marsh is so named after Captain W. H. Bacchus, who 

 settled here with stock in 1838. Old maps show an area of marshy 

 land near by, on the Lerderderg River, less than a mile from the 

 place marked " Bacchus Station " (see Quarter Sheet 12 N.E.). 

 No trace of this marsh now remains as the land is all drained and 

 tilled — there is scarcely any doubt, however, that this marshy area 

 gave the name to the locality. 



X.— Economic Importance of the Physiographic 

 Features. 



The economic bearing of the various physiographic factors has 

 been borne in mind throughout the paper, and frequently referred 

 to. In this section the matter will be dealt with in the undermen- 

 tioned order. Reference to the sections shown in Figs. 12 and 13, 

 and the block diagram (Fig. 40), will be found helpful, while the 

 large map (Plate XI.) has been specially drawn to illustrate this 

 portion of the paper. 



