86 PROFESSOR T. MCKENNY HUGHES, M.A. 
lowlands. Underground passages, high above the present 
water-channels, were swept clean by the body of water forced 
through them under enormous pressure. Caves that had 
been sealed up for years with barriers of stalagmite, which 
one would have thought might have defied the rush of any 
flood, were burst open. Most of this débris—all, in fact, 
that was moved by the first rush of water—was carried down 
the valley. Some remained around the mouth, and some in 
embayed corners in the caves. Here we saw fragments of 
stalagmitic floors, mixed up with débris washed in from the 
swallow-holes above. Some might have seen here evidence 
that, after the cave had been formed and occupied and 
gently filled by earth, and coated and partitioned by stalactite 
and stalagmite, there came an age of flood,— perhaps of 
submergence,—when the old deposits were re-sorted, the old 
floors broken up, and that the cave then entered upon 
another phase of its history. How different the facts! I 
saw this revolution taking place. It was all over in three 
short hours. It was another illustration of the great law of 
Uniformitarianism, which I have heard the Duke of Argyll 
well state thus: Local catastrophic action is not inconsistent 
with continuity of causation. 
We must bear these things in mind when we are examining 
cave-deposits. 
The peat torn away from the mountain-side above was so 
beaten up in this great natural churn that the water cf the 
tarn did not get clear for months. The sediment did not 
settle for three weeks in a long glass which I filled during 
the flood. There must have been a layer of fine carbonaceous 
clay formed over the bottom of the tarn and in many a 
deep cave-pool after that storm. When the rain ceased, the 
water soon ran off the mountain-side, and I went up to 
examine Gaping Gill, the great swallow-hole that feeds the 
cave. I found a passage opened out among some blocks on 
one side of the stream a little above the chasm. I thought I 
might perhaps find a zigzag descent, which would lead me 
down into Gaping Gill Hole. So I crept in. 
- I soon got beyond the light, and therefore took the pre- 
caution of throwing stones in front of me before I advanced. 
I found the slope increased rapidly, and then all of a sudden 
the stones dropped into a deep hole, down which they 
whirred, knocking the sides here and there till they dropped, 
with a booming noise, into deep water below. I wriggled 
out, and returned another day, with friends and candles and 
string, for I could not drop the stones straight so as to clear 
the sides, and so estimate the depth by the time they took in 
