QA 
x THE GEELONG NATURALIST. 
A glance atthe geological map of Victoria shows the 
volcanic formation stretching from Melbourne westward, with 
scattered patches in Gippsland and midland Victoria. Our 
more immediate study is that part of the Western District 
lying between Colac and Mt. Gambier. This will take in all 
those centres of igneous activity, which, as we shall mention 
hereafter, made this corner of Australia one of the liveliest 
spots in the world. Wandering idly over the conical hills, 
and around the depressions now occupied by lakes, and 
picking up fragments of stone almost as light as pumice, and 
bearing to the veriest tyro unmistakable traces of the action 
of fire, one naturally asks the questions :—How long have 
these craters been silent? Is there any possibility of their 
again resuming their former activity and scattering destruction 
among the surrounding inhabitants ? 
Time in geology is not reckoned by years. 
The aborigines of Western Victoria had ‘traditions of 
great fires once burning in these plains, but these traditions 
may have been handed down from generation to generation. 
Then again the blackfellow is a keen observer of nature, and 
seeing the evidences of the devouring element on every hand, 
he would, as a matter of course, do as his learned white 
brother has done—form a theory to account for this, and to 
his own satisfaction. So the mere fact of the traditions of 
the blacks can give little data in estimating their age and most 
recent eruptions. 
The ravages of volcanic eruptions are, however, very 
soon erased by the vegetation produced by the rapid decom- 
position of the upper surface of the erupted materials. 
One fact is known with certainty. These great outflows 
of lava overlie tertiary deposits of eocene periods. In several 
instances on the plains, the strata of lava have been bored 
through, and the above deposits found, and at Mt. Gambier, 
near Hamilton (Muddy Creek), and near Camperdown, the 
same deposits outcrop. 
Let us view in more detail some of the characteristic 
features of this region. After leaving Colac and travelling 
for ten miles, the traveller by coach or train enters the 
curious district termed, very happily, * The Rises." The 
journey by either road or rail will give him a fair indication 
of the nature of this peculiar formation, though the more 
rocky and rugged features do not appear near the line. To 
,describe the Rises in a picturesque manner is beyond the 
