162 GLACIAL ACTION IN TASMANIA. 
the foot of the Oakleigh Range, Between these branches 
of the Forth there is a ridge rising to a height of 
perhaps 150 feet above the level of Lake Eyre, and 
highest at the north end. The whole of this ridge 
is a succession of roches-moutonnées of the most typical 
shapes, with long rounded stopes towards the south, and 
short steep ones towards the north, the direction of motion 
of the glacier having been northward down the valley of the 
Forth. Between the hummocks are numerous small ponds 
and tarns, with their bottoms much deeper than their outlets. 
Some of these are grown over with swampy vegetation, and 
form minute peat mosses, but many still show their rocky 
beds. Towards the south end of the ridge the country rock 
is mostly schist, and though the general shapes of the roches- 
moutonnées are well marked and characteristic, striations on 
the rock surface have been obliterated by the weathering of 
the exposed surfaces, but further north, where the rock is a 
very dense and hard quartzite, the planed surfaces: are 
wonderfully clear, and it is difficult to find a place where 
a stone showing the smoothed surface can be knocked out of 
them, so little disintegration of the rock has taken place. 
Owing to the extreme hardness of the quartzite the surfaces 
are not as arule striated, but polished smooth, often almost 
as smooth as glass. All over the ridge numerous erratic 
blocks of greenstone are scattered, and as this part of the 
ground is separated by valleys from the slopes of the surround- 
ing hills running up to the greenstone cappings, and there is 
no possibility of their having been carried uphill by running 
waters, it is plain that these have been transported to 
their present situatians by ice. It serves to give some idea 
of the antiquity of the ice action that these greenstone erratics 
are very little decomposed, being as sound and unweathered 
as the stones lying on the tops of Mount Wellington and 
Ben Lomond. When we consider that the greenstone is a 
felspathic rock, and weathers rather easily (the stones of it in 
the neogene tertiary drifts round Launceston, for example, 
being generally pretty thoroughly decomposed), we see that 
the date of the glaciation must not be referred to the very 
distant past, but is more likely to be pleistocene. The 
splendid state of preservation of the ice-worn surfaces also 
favours the view that they are not very ancient, for even a 
quartzite must suffer considerable disintegration if exposed to 
rain and frost, such as every winter brings in this high-lying 
part of {the country, at an altitude of between 2,000 and 
3,000 feet. The evidences of glacial action seen by Mr. Moore 
also appear from the description to indicate a comparatively 
recent date. 
The high narrow plateau lying between Mount Pelion and 
Barn Bluff shows in its every contour the former presence of 
