of distant thunder. The voice of song was raised on this dark, deep
water, and the sound was as that of the most powerful choir. A fall
band of music on this river of echoes would indeed be overpowering.
The aquatic excursion was more to our taste than any thing we had
seen, and never can the impression it made be obliterated from our
memories.

The Echo is three quarters of a mile long. A rise of the water of
merely a few feet connects the three rivers. After long and heavy
rains, these rivers sometimes rise to a perpendicular height of more
than fifty feet; and then they, as well as the cataracts, exhibit a
most terrific appearance. The low arch at the entrance of the Echo,
can not be passed when there is a rise of water of even two feet. Once
or twice parties have been caught on the further side by a sudden
rise, and for a time their alarm was great, not knowing that there was
an upper cave through which they could pass, that would lead them
around the arch to the Great Walk. This upper cave, or passage, is
called Purgatory, and is, for a distance of forty feet, so low, that
persons have to crawl on their faces, or, as the guides say, _snake
it_. We were pleased to learn that this passage would soon be
sufficiently enlarged to enable persons to walk through erect. This
accomplished, an excursion to Cleveland's Avenue may be made almost
entirely by land, at the same time that all apprehensions of being
caught beyond Echo will be removed. It is in these rivers, that the
extraordinary white eyeless fish are caught--we secured two of them.
There is not the slightest indication of an organ similar to an eye,
to be discovered. They have been dissected by skillful anatomists, who
declare that they are not only without eyes, but also develope other
anomalies in their organization, singularly interesting to the
naturalist. "The rivers of Mammoth Cave were never crossed till 1840.