296 
A BOTANICAL TOUR THROUGH SOUTH WALiES, &C. 
emerges, solemn and tamed, into the fair light of heaven. The summit of the 
rock where the river enters the cavern is about sixty feet above the level of the 
water ; but the opening in the rock itself does not extend twenty feet in height, 
and is about forty-five in breadth. It is to be observed that the stream, on enter¬ 
ing, divides itself, one arm taking a winding course to the left, and forming in its 
passage deep perforations and fathomless pools, and the other proceeding with a 
wider current, leaving at first a space to trace its course, but at length filling up 
the cavity with its waters. Besides these two main tunnels, there are several 
lateral ones, which may be threaded, but all are so dark that candles are neces¬ 
sary. I had felt inclined to have pilgrimaged through the entire cavern, having 
understood from several authors that there was a practicable passage ” through it. 
I soon found that this practicable passage was only one for a fish or a Duck, the 
fact being, that where the river emerges no entrance or exit, but for an amphi¬ 
bious being, can possibly be obtained. By fording the stream, and taking the 
right-hand defile, of which it might not unaptly be said— 
‘‘ Hinc via Tartarei qu£e fert Acherontis ad undas,” 
I was able to advance rather more than 150 yards over very slippery rocks, po¬ 
lished by the floods that frequently cover them, and which, excavating whirl- 
holes, render progression a tedious affair; for, of course, a slip would, as indeed I 
experienced, leave one floundering in the dark. Beyond the distance stated, I 
found there was no advance, the stone gradually sloping off in an inclined plane 
down to a black deep pool, which I ascertained by poking down on hands and 
knees till I felt the water. I then gave it up. This passage is, however, -worth 
exploring, as in one place the roof expands in gloomy obscurity into a rude but 
lofty dome, a crevice in which, near the top, admits a trembling ray of 
light, that timidly progresses about half-way down, and just serves:ffaintly 
to show the outline of a roof that would otherwise appear illimitablejqftlt 
is remarkable, that the coppice covering the external roof or bridge formed 
by the embogueing river, is covered with stony debris, as if anciently over¬ 
flowed with water, but whether this was occasioned by some extraordinary inun¬ 
dation, or whether in fact the river itself did not originally flow there—though 
now delving for itself a subterranean passage—I leave for more matured consi¬ 
deration. 
On the smooth blue limestone slabs just before the mouth of the cave I found 
a gelatinous plant belonging to the AI^cb GloiodadecEy about the size of a human 
ear. It exactly resembled a thick piece of glue soaked in water. Having been 
able to meet with no certain account of it, I describe the plant. It appears to 
belong to the genus Palmella in the Nostochinece^ tribe 21 of the AlgcB in Sir J. 
W. Hooker’s British Flora. Dark olive green or brown gelatinous Palmella^ 
