266 
TR THE GEELONG NATURALIST. 
Closely akin to peat is a substance which was much discussed in 
our colony a few years ago, I refer to brown coal. 
The main difference is that brown coal has lost nearly all out- 
ward appearance of its origin, and has taken on something of a 
mineral nature. Brown coal occurs in the Tertiary formation. Both 
peat and brown coal have been proved capable of being converted 
into coal, peat under a pressure of 6000 atmospheres. 
Leaving now for the present the general consideration of allied 
growths, let me illustrate by a peat deposit with which I have been 
familiar for years, the conditions favourable for a good peat bed. 
About 5 miles from Cobden 
is the Cobrico Swamp and lake. 
By giving a vertical section you 
perceive a gently sloping bank, 
no presence of salt in the soil, 
with only an indifferent slope for 
an outlet. Here we have a 
hollow about 20 feet deep once occupied byalake. As the vegetation 
on the shallow rim of the lake encroached more and more, encouraged 
by theaccession of nutriment washed from the hills around, at last only 
a pond of a few acres has been left in the deepest, and probably 
most protected from sediment, part. This little lake gives evidence 
itself of such a history, its banks, if banks they can be called, are mere- 
ly the surrounding peat, and these often overlap, to the great danger of 
stock, which get'in but can find no secure hold when they attempt 
to clamber out. Asin most peat swamps the substratum is clay, 
with no trace of gravel aboveit. Good sized logs of wood were found 
embedded in the peat, but in this case they were merely trees, which 
had grown on the higher and drier portions of the peat, and having 
fallen had been gradually covered. The loose porous nature of the 
mass and its liquid nature were well exemplified years ago in its 
drainage. During that process, eels were occasionally dug out and 
captured by the men employed. But when, after the first eel or 
two were thrown out, the next to engage the attention of the men 
was a villainous blaek snake, and as these black snakes alternated 
pretty fairly with the eels, the rush for the eels considerably abated. 
This peaty ground when drained becomes solidified on the surface 
and forms magnificent agricultural and grazing land. 
Surface of Peat; Lake, Peat. 
Nature, however, though it may be helped, mustnot be frustrated. 
To clear the swamps of tea-tree roots, its surface was frequently 
burnt. Where this was allowed till the whole surface to a depth of 
18 inches had been burnt off, the sour under portions took years to 
. preduce a crop. I 
