e of the rock is carried into some deeper and yet undiscovered
cavities beneath. The floor itself gradually sinks, the domes grow
higher, and the walls recede as long as the water continues to drip into
them.

It is not unreasonable to suppose that the substratum of limestone in
all the country for many miles in the vicinity is perforated with these
tremendous shafts; as those which are seen in the cave are only such as
happened to be in the course of the tunnels composing the Mammoth Cave.
It is not improbable that there are many others on every side, close to
the line of the tunnels, but not yet connected with them.

In any one of the above-mentioned departments, the description of one
place answers for most others, except in dimensions. The following are a
few out of many hundreds of measurements taken in as many different
places:--

The "Rotunda," the first chamber from the entrance of the cave, is about
one hundred feet high, and one hundred and seventy-five in diameter.

The "Methodist Church," eighty feet in diameter, and forty in height.

"Wright's Rotunda" is four hundred feet in its shortest diameter, being
nearly circular; the roof seems perfectly level, and is about forty-five
feet high.

"Kinney's Arena" is a hundred feet in diameter, and is fifty feet high.

"Proctor's Arcade" is one hundred feet in width and three quarters of a
mile in length. The walls, which are about forty-five feet high, are
nearly perpendicular throughout the whole length of the arcade, joining
the roof nearly at right angles, and are so smooth that they look like
hammer-dressed stone.

"Silliman's Avenue" is a mile and a half in length and about forty feet
in height, its width varying from twenty to two hundred feet.

"Shelby's Dome" and the pit beneath it are two hundred and thirty-five
feet in height, and about twenty-five in diameter.

"Mammoth Dome" is two hundred and fifty feet high, and nearly one
hundred in diameter.

"Lucy's Dome," the highest in the cave, is sixty feet in diameter, and
three hundred in height.

Nine miles from the entrance of the cave is the "Maelstroem," a dry pit
or well, one hundred and seventy-five feet deep, and about twenty in
diameter; and from the bottom of this shaft may be seen the openings to
three other avenues, which lead farther into this Plutonian labyrinth
than mortal foot has ever trod.

Although the distance of nine miles is about as far as tourists usually
get from the ent