thirty feet above, you will see a large cave, connected with which is
a narrow gallery sweeping across the Main Cave and losing itself in a
cave, which is seen above to your right This latter cave is the Gothic
Avenue, which no doubt was at one time connected with the cave
opposite and on the same level, forming a complete bridge over the
main avenue, but afterwards broken down and separated by some great
convulsion.

The cave on the left, which is filled with sand, has been penetrated
but a short distance; still from its great size at its entrance, it is
more than probable, that, were all obstructions removed, it might be
found to extend for miles.

[Illustration: ENTRANCE TO THE GOTHIC AVENUE.
On Stone by T. Campbell
Bauer & Teschemacher's Lith.]

While examining the old saltpetre works, the guide left us without our
being aware of it, but casting our eyes around we perceived him
standing some forty feet above, on the projection of a huge rock, or
tower, which commands a view of the grand gallery to a great extent
both up and down.

Leaving the Main Cave and ascending a flight of stairs twenty or
thirty feet, we entered the Gothic Avenue, so named from the Gothic
appearance of some of its compartments. This avenue is about forty
feet wide, fifteen feet high and two miles long. The ceiling looks in
many places as smooth and white as though it had been under the trowel
of the most skilful plasterer. A good road has been made throughout
this cave, and such is the temperature and purity of its atmosphere,