The river is about 10 feet wide, and from 12 to 18 inches deep. The length visible is about 60 yards. The overhanging rocks range from 5 or 6 feet to 70 feet in height. From one end of the river comes a sweet soothing sound, made by water-friction. This proves the existence of a considerable current, but the fluid is so limpid and smooth that the eye cannot detect its motion. It is demonstrated, however, in another way. The curator cuts little sections of sperm candle, and, after lighting the wick, floats them on the river, whereupon they immediately begin to glide down the stream, the course of which is nearly south-east. The effect is extremely pretty. Not only are the lights themselves sharply mirrored below, but there is a perfect reflection of the rocks above. Near the tunnel by which the water emerges N.N.W. is a mass of overhanging formation, duplicated in a natural mirror. The bed of the watercourse is dark, being covered chiefly with mud and grit and a few water-worn pebbles. The rocky walls are of limestone--white and black. Up the channel N.W., about 40 yards, is a good crossing-place--not in old Charon's boat, but by means of an ordinary deal plank. On the other side of the river is a ledge of rocks with pebble drift concreted with a substance somewhat resembling the cement in which diamonds are found, and the pebbles, although larger, are of the same shape and blackness as those commonly associated with the luminous gems found in their natural state at Kimberley, in South Africa, or in the Tenterfield district of New South Wales. On turning the light of the magnesium lamp up the river, its rocky ledges are seen to be ornamented with stalactites and formation perfectly mirrored in the water, which is about 600 feet from the surface, and about 50 below the level of the Cave House in the centre of the valley. Never had river more romantic barriers. Human imagination could not conceive a freak of nature more wildly grand or mysteriously beautiful. There are large ornamented pillars near delicately-tinted formation, drooping from overhanging rocks, like pensile boughs of weeping willow. Some of the twigs skim the surface of the stream, and others are bathed in it. Beyond is a water-hole about 40 feet long, and from 16 to 20 feet wide. Because of its wonderful clearness, it is difficult to judge of its depth; but it has been tested to the extent of five feet, and probably at the extreme point where the water flows from the tunnel it may be six or seven feet deep. The effect of the brilliant light is superb. The ornamentation on the roof of the tunnel is reflected and transposed in the mirror below, each reflected stalactite having the appearance of a twin stalagmite rising from the river bed, which may be traversed for about 150 yards.