104 Charles Fenner : 



IV.— Mountains and Hills. 



As stated in the last section, differences of general elevation 

 appear to have played a large part in producing the diverse 

 features of the four divisions. Generally speaking, we may sum 

 these differences up as follows (see Plate XIX.) : — 



A. — Low, flat, gently sloping south-west ; average elevation 



2-300 feet, rises to 400. 

 B. — Higher land, fairly level, difficult to detect any general 

 direction of slope, but probably slopes to north and 

 west; average elevation 4-500 feet. 

 C. — Comparatively high lands, average 7-900 feet, rises in 

 the western part to 1500 feet, and in the east to 3000 

 feet and over ; deeply dissected by streams flowing in all 

 directions from a central east-west ridge. 

 D. — Somewhat similar in elevation to area B, but with 

 much more diversity of hill and valley; variety also 

 introduced by volcanic hills and flows. 

 Apart from these considerations of elevation, the chief cause of 

 the present disposition of the Glenelg and its tributaries lies in 

 the manner of their growth. The basin of this stream, although 

 itself of comparatively recent origin, appears to have still more 

 recently, added greatly to its territory in two ways : — 



(i.) Aggressively, by the capture of less fortunately situated 



streams, 

 (ii.) Passively, by the diversion of neighbouring streams into 

 the Glenelg basin on account of lava flows. 

 These possibilities will be dealt with more fully in a later section. 

 Meanwhile, having accomplished- a general survey of the whole 

 area, we may deal with hill and valley in somewhat more detail. 



(a) Grampians and Dundas Highands. — In these mountains most 

 of the streams in the basin have their origins. They form the 

 outstanding mountain feature of western Victoria, and consist of 

 upper palaeozoic indurated sandstones and quartzites. block- 

 faulted, with faults roughly north and south, the scarps facing east 

 and the dip slope to the west. The Grampians were discovered and 

 named by Mitchell, who in 1836 ascended the highest peak. Mount 

 William (3827 ft.), and spent a freezing night on its summit. 

 Mount Dundas (1535 ft.) is the extreme western member of the 

 group. 



(b) Continuation of the " Main Divide." — One point is worthy 

 of discussion here since it bears on the question of the Main Divide 



