Observations on Mount Mary. 157 



one, were found here, and numbers of pebbles of quartz, either 

 intact, or more or less flaked. Few flakes were noticed away 

 from the summit, or high up along the sides, thus indicating that 

 the aboriginals used the mount as a look-out and rendezvous. It 

 gives a most extensive view across the country in every direction, 

 especially over the treeless Werribee Plains, and towards the 

 Brisbane Ranges and the You Yangs. 



The only trees on the mount are a few sheoaks, and an 

 occasional lightwood, though a few eucalypts grow in the vales 

 below, and fine specimens of them may be seen along the 

 Werribee River, where, also, there are several other kinds 

 of trees, conspicuous among them being the native laurel. 



On examination of the natural sections, and the road cuttings 

 at the bridge over the Werribee, one and a half miles east of 

 Mount Mary, it is seen that at least two flows of basalt are 

 present, separated by thin beds of tufi" and lapilli ; while along 

 the river, near the sharp bend in the N.E. corner of Allot. 25b, 

 parish of Werribee, as shown in the Quarter-sheet, a fine natural 

 section is visible in the cliffs. The following note thereon 

 describing this section, is as follows : — " 28 feet hard scoriaceous 

 basalt, laminated and jointed; 24 feet soft friable basalt, with 

 hard imbedded nodules; 9 feet volcanic ash; 13 feet thin 

 laminae of soft decomposing scoriaceous basalt ; 30 feet soft friable 

 basalt, enclosing nodules and irregular bands of augitic basalt." 



These tuffs consist of a firmly cemented fragmentary rock, 

 comprising a mass of subangular and rounded grains of sand, 

 and fragments of basalt, scoriae, and tachylite, up to the size of 

 grains of sand througli which are distributed larger pieces of 

 scoriae and vesicular basalt. The scoriae fragments are mostly 

 decomposed into yellow clay. 



Interbedded with these are thin bands of very fine material — 

 volcanic dust — which forms a coherent rock, while along bedding 

 and joint planes and exposed places, a thin crust of carbonate of 

 lime has been deposited. This gives the rock a pretty, white 

 appearance, noticeable from a long distance. The coherent 

 nature of these tuffs seems to indicate that they were mixed with 

 a considerable quantity of water prior to deposition and were not 

 accumulations of dry material. 



