Returning by the same path for a considerable distance, another cavern, which branches in a south-west direction from the one already explored, presents itself. The roads here are still more difficult of access, but the stalactites are certainly most beautiful. Many of them, more than a yard in length, are pendent from the roof, and the greater part do not exceed the dimension of the smallest reed. The top and sides of this cavern are remarkably smooth, particularly at the part called the Amphitheater. In general, the stone is of a very dark color, to which the transparent appearances before mentioned, with each a drop of water hanging at its extremity, form a fine contrast. SPEEDWELL LEVEL. In the Speedwell Level, or Navigation Mine, in the vicinity of Castleton, art has been combined with the subterraneous wonders of nature. Being provided with lights, the guide leads the visitor beneath an arched vault, by a flight of one hundred and six steps, to the sough or level, where a boat is ready for his reception, and is put in motion by pushing against pegs driven into the wall for that purpose. After proceeding about one-third of a mile through various caverns, the level bursts into a tremendous gulf, the roof and bottom of which are invisible, but across which the navigation has been carried, by throwing a strong arch over a part of the fissure where the rocks are least separated. Here, leaving the boat, and ascending a stage erected above the level, the attention of the visitor is directed to the dark recess of the abyss beneath his feet; and firm indeed must be his resolution, if he can contemplate the scene unmoved, and without an involuntary shudder. To the depth of ninety feet all is vacuity and gloom; but beyond that commences a pool of Stygian waters, not unaptly named the Bottomless Pit, the prodigious range of which may in some measure be conceived, by the circumstance of its having swallowed up more than forty thousand tuns of rubbish, made in blasting the rock, without any apparent diminution either of its depth or extent. The guides assert that the former has not been ascertained; but there is reason to believe that its actual depth in standing water is about three hundred and twenty feet. There can not, however, be a doubt but that this abyss has communications with others still more deeply situated in the bowels of the mountain, and into which the precipitated rubbish has found a passage. The superfluous water of the level falls through a water-gate into this profound caldron, with a noise like a rushing torrent. This fissure is calculated to be about eight hundred feet beneath the surface of the mountain; and so great is its reach upward, that rockets of sufficient strength to ascend four hundred and fifty feet, have been fired without rendering the roof visible. The effect of a Bengal light discharged in this stupendous cavity, is extremely magnificent and interesting.