10 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
while at intervals copious large bubbles of gas are emitted. 
I am told by Mr. P. H. Welch that this gas extinguishes a 
match, a statement which, unfortunately, I forgot to test; 
but the circumstances would imply that the gas is carbon dioxide. 
The water has a distinctly, but not specially, salt taste. 
As to the nature of the contiguous vegetation, a question 
that will arise in the minds of most botanists, though I made 
the most careful search that I could, (with an ardour somewhat 
dampened, I confess, by the continuous downpour of rain that 
prevailed during our visit), I could find no trace of halophilous 
or salt-marsh plants, such as occur so copiously at the Sussex 
salt springs, as described in Note No. 7. 
In the vicinity of the salt springs the stream runs more 
quietly in a rather open country, through gravel-bottomed 
stillwaters and pools, winding so greatly as to have acquired 
for this part of the river the name of Round Turns. A good 
mile below the springs, however, after receiving large branches 
on both sides, its character gradually changes, and it proceeds 
to broaden and run in shoal rips over a schistose instead of 
a sandstone bed. Three or four miles further down, where 
it receives a fine branch from the east and still runs in con- 
tinuous shallow rips, the stream is entering a region of high 
stony bluff or cliff banks, composed of schistose slates, and 
soon is zigzagging in abrupt turns among cliffs whose crys- 
talline aspect and varied vegetation is a great surprise in 
this sandstone country, and suggestive rather of northern 
rivers, like the Serpentine. Of course this is the area of 
Devonian rocks indicated upon the Geological map and 
mentioned in the Reports. This character culminates some 
two miles below the McIntyre Brook, after which the valley 
walls, while preserving for a time their general aspect, gradu- 
ally open and fall off, though the river bed continues broad 
and shoal, making the canoeing markedly difficult. Gradually 
the country opens out still more, and the stream becomes 
quieter and deeper while some intervales appear, and the 
uppermost settlement, and then the upper bridge, is reached. 
A mile below this bridge appear the waterlogged stumps and 
