AccoLLiit of Glacial Deposits of Bacchus Marsh. 53 



true till, or moraine profoiide. This till can be traced down 

 the Werribee to its junction with the Myrniong Creek, and 

 a little way beyond on the latter Creek. It liere is appa- 

 rently overlaid by the Tricvssic rocks. With heavier tools 

 than we had at our disposal, and a little more time, it would 

 not be diiiicult to remove more of the till from the under- 

 lying Silurian, and thus lay bare more of the moutonnee 

 surface. 



A few days after this discovery, we received a letter from 

 Mr. Brittlebank, stating tliat he had found a further example 

 of roche moutonnee at the lower end of the Werribee Gorge, 

 nearly two miles below its junction with the Myrniong. 

 On our next visit, we accordingly proceeded to the spot, and 

 examined the rocks in question. 



The Gorge has been cut to a depth of over GOO ft. through 

 a mass of Silurian rocks, flanked by the Triassic sandstones 

 and conglomerates, the former having formed a ridge or 

 island in the Triassic sea or lake (Fig. 1). The Silurian 

 rocks heie consist of slates, finely laminated shales, and hard 

 quartzitic sandstones ; quartz veins are frequent, and a dyke 

 of porphyry also occurs. The strata are inclined at the 

 usual high angles, being often almost vertical. 



At the place indicated b}^ Mr. Brittlebank we found the 

 till again overlying the Silurian. Here, it presents much the 

 same ajipearance as that last described, glaciated stones and 

 pebbles being frequent. At this point, at a spot where the 

 till was only about a foot thick, Mr. Brittlebank had laid 

 bare a portion of the underlying rock. An exoniple of 

 roche moutonnee was thus exposed to view, which was even 

 better than the one h'lst discovered. More of the overlj'ing 

 deposit was now removed, and a greater surface of the 

 nnderl3'ing rock uncovered, this being an operation of some 

 difficulty. The surface exposed ])resented the apjjearance of 

 three smooth parallel ridges, well scored and striated, with 

 well rounded grooves six or more inches deep between. 

 Here, as before, the stride and grooves run noi-th and south, 

 in the direction of the strike, and right across the river 

 (PI. XI). In several places, the rock has been fractured at 

 right angles to the groovings. Photographs of these were 

 obtained. This was by no means the only spot in this 

 locality where roches moutonnees were found. A short 

 distance further up the Creek can be seen a niunded 

 huunnock of Silurian rock, which has been denuded of the 

 overlying till. The effects of weathering have obliterated 



