Upper Palaeozoic Pocks* 
49 
Commencing with the western area, we find the ranges of the 
Grampians composed of a group of sandstones which rest partly 
on granite and trappean rocks, and partly on metamorphic and 
Lower Silurian strata. 
As no further scientific examination has been made of the 
Grampian Sandstones since the publication of Mr. A. K. C. 
Selwyn’s work in 1866, 1 cannot do better than quote that gentle- 
man’s observations : — 
* * “A thickness of upwards of 2,000 feet is ex- 
posed in the precipitous escarpments of the Grampians, Mount 
Sturgeon, Mount Abrupt, and the eastern face of the Victoria 
Ranges. The lithological character of the series, as exhibited in 
the Grampians, is strictly arenaceous — massive thick-bedded sand- 
stones, with bands of sandy flags, but no slaty or slialy beds. 
Considerable varieties occur in texture and composition, from very 
hard siliceous grit and quartz rock, with included pebbles of white 
quartz (as at Mount Talbot, Mount Arapiles,and the Black Range), 
to hard and soft fine-grained freestones. The prevailing colours 
are shades of whitish-brown, reddish-brown, and white, and 
rarely brick-red. Much cross-stratification or false bedding is 
observable, but the whole formation has a westerly dip at rather 
low angles, giving a gentle slope to the face of the hills in that 
direction, whilst to the eastward the beds terminate abruptly in 
bold rocky escarpments and almost vertical cliffs several hundred 
feet in height. (Fig. 12.) 
“ In the Dumlas and Black Ranges, the dip of the beds is 
reversed or to the eastward, indicating a synclinal axis between 
these hills and the Grampians, Sierra, and Victorian Ranges. 
“In some places the beds are seen to rest directly on grauito 
whilst in others they rest on the up-turned and denuded edges of 
the Silurian strata.” 
During a very brief visit to that portion of the country, I found 
that the rocks of the Dundas Range form an isolated patch of the 
same character as, and evidently once continuous with, the rocks 
to the eastward. 
The intermediate portious have been removed by denudation, 
and the subjacent metamorphic rocks have been laid bare on 
the western side of a broad valley, occupied principally by 
Tertiary deposits, which extends from Cavendish to the Glenelg, 
and separates the Dundas from the Sierra and Victoria 
Ranges. 
To the north, Mount Arapiles, and several smaller hills com- 
posed of the same rocks, form tolerably lofty isolated outcrops, 
