NEW BRUNSWICK CAVES. 
161 - 
is one of the peculiarities of that quarry ; the water having been 
formerly discharged by outlets through the underlying limestone 
and thence to the bed of the river. 
It is in connection with these gypsum deposits that the ice 
pits and the subterranean lake referred to by Prof. Ganong in 
Bulletin XXI occur, both of which have been visited by the 
writer, and in one of which he found several feet of snow in the 
latter part of July. Of the underground lake, so called, on 
Demoiselle creek, Mr. Osman has kindly furn:’shed me with the 
following description : 
“ The gypsum deposit in which the depression occurs pre- 
sents a high front, probably 90 or 100 feet high, of anhydrite, 
containing some seams of hydrous gypsum, to a very limited 
extent, and at the base of this wall of hard rock the little 
Demoiselle brook ripples peacefully along. At the back of this 
wall of anhydrite, more or less hydrous gypsum has been found, 
but not to any large extent, as immediately to the back of it red 
marl-like limestone and conglomerate has been exposed after 
limited operations ; but a certain wash has taken place, or per- 
haps solution of the soft rock, which eventually resulted in find- 
ing an outlet for the water collected in the pocket so created 
through one of the seams of soft gypsum in the anhydrite wall, 
and eventually emptied into the Demoiselle brook, wearing away 
as it went more or less of the soft gypsum, and making this 
underground cavern probably about forty feet in width and about 
200 feet in length. Without taking anv levels, I think the level 
of the water running through this cavern is pretty nearly the 
same as the water in the brook, as at the point where it is deepest 
it is very still, although there is some current in it. Therefore, 
I surmise that the present source of this little basin of water is 
from up the brook, and that it flows in at the upper end and out 
to the brook again at the lower end. 
“ As near as I can estimate, it is perhaps fifty or sixty feet 
from 'the level of the plaster heads at the back of the hard face 
and down to the surface of the water in the little lake, and in 
