High overhead springs an arch eighty feet wide and resting on vertical walls. Presently the guide calls our attention to the exit of the Corkscrew, on our left, an extraordinary passageway by which we are to return after visiting the River Hall. If we happen here as another party is returning, a curious effect is produced by their torches emerging one at a time in a procession winding down the Kentucky Cliffs. But now we advance along the worn cart-road made by the saltpeter miners, strewn by their ancient log-conduits, which are strangely preserved during the century that has elapsed since some of them were first brought hither. Lift one and you will be astonished to find how light they are. At the junction of the Main Cave and Archibald Avenue is the “Church,” where the pious miners used to hear the message of salvation taught by itinerant preachers, and where in more recent days many a sermon has been preached and many a psalm been sung, awakening echoes from the cavern walls. [Illustration: Leaving the “Corkscrew”] Reserving the Gothic Avenue for another visit, we note, as we pass along, the grotesque figures of animals and birds made by the deposits of the black oxide of manganese overhead. Mark well the Standing Rocks, which fell edge-downward ages ago, set free from the roof possibly by some earthquake shock. Now we walk awe-struck under the Grand Arch, where the guides effect a marvelous surprise by means of simple illumination. They burn chemical fires at a point near the saltpeter vats, some five hundred feet to the rear of us, and the contour of the walls brings out a statuesque effect which is aptly styled “Martha Washington’s Statue.” It requires but little play of the imagination to fancy it a marble representation of that eminent lady of Colonial times. An immense rock lies near the right-hand wall, forty-five feet long, eighteen feet wide, and fifteen feet high, which used to be called the Steamboat; but it is now known as the Giant’s Coffin. The quasi-sarcophagus may have been torn from the adjacent wall by some convulsion, or it may simply have fallen and lodged in its present suggestive position. Its weight is estimated at two thousand tons. It is one of the great landmarks, and though we should pass it many times it is impossible to do so without being impressed by its solitary grandeur, rivaling as it does the blocks of Baalbec in Syria.