164 GLACIAL ACTION IN TASMANIA. 
hummocks and rounded ridges continue to be met with on 
the high lands, and descending suddenly ana abruptly from 
these are huge deep ravines and valleys. It is noticeable 
that in many of these the streams in the bottom of the 
ravines are quite insignificant in size, and not at all likely to 
have been sufficient to eat out such huge valleys. Even where 
they are fairly large rivers, as in the case of the Fury, Forth, 
Bluff, and Sophia rivers, it may be noticed that the sides of 
the gorges have on the whole broad flat slopes, and present a 
generally even outline; they are scarred with deep little 
ravines, it is true, in which there are watercourses, but these 
from a little distance are almost invisible. This points to the 
likelihood of the main deep gorges having been the beds of 
glaciers, the erosion by running water since the retirement of 
the ice having been sufficient to greatly alter the contours 
shaped by the latter. All across from Barn Bluff to Mount 
Reid the solid rock seems to be immediately under the very 
shallow surface soil, both on the ridges and in the valleys, as if 
there had not been time for the formation of accumulations 
of superficial debris to any considerable extent since the 
times when the ice planed away all the loose stuff covering 
the solid rock. Throughout this district the contours of the 
hills are on the whole wide, broad, and flat slopes, not the 
sharp, jagged, broken outlines which we should expect to 
find in schist and quartzite country carved only by running 
water. 
The lakes at the head of the west branch of the Murchison 
River, and on the divide between it and the Henty, Lakes 
Spicer, Dora, Beatrice, Rolleston, Julia, Selina, etc., also pro- 
bably indicate the former presence of glaciers, and I think 
we must come to the conclusion that the whole of the deep 
gorges among these western mountains, now occupied by the 
headwaters of the Pieman, Henty, and King Rivers, have 
been at no very distant period of time occupied by rivers of 
ice. The erratic blocks noted by Mr. R. M. Johnston in the 
Mackintosh Valley quite bear out this conclusion. It is very 
likely that the ice had retired from the low-lying valleys long 
before it finally disappeared from the tops of the ranges, just 
as in the New Zealand Alps we find indications that the present 
glaciers once extended much lower down, and therefore the 
smoothed surfaces at Mount Pelion and Lake Dora may be 
of xuch later date than the erosion of the main valleys, but 
nevertheless it seems probable that the whole of the present 
shape of the country along the West Coast Range is due to 
ice action of comparatively recent date. 
If we allow that the deep valleys at the head of the Pieman 
were once occupied by glaciers, we must admit that the ice 
came down to within 500 or 600 feet of the present sea level, 
for these gorges are very deep, or perhaps we should rather 
