each pillar, and fire-flies flitting from branch to branch.
The Chief City or Temple, situated in the main cave beyond the Rocky Pass, is rarely visited by strangers now, yet, before the discovery of the rivers and the wilderness of beauty beyond, it was considered one of the great features. It is an immense chamber, excelling in size the cave of Staffa. The floor at different points is covered with piles of rocks, presenting the appearance of an ancient city in ruins.
Three miles beyond Chief City, the main cave is terminated abruptly by rocks fallen from above, which, if they could be removed, would no doubt open communication with a cavern similar to the one we have been exploring. So many wonders, viewed in a few hours, leave the mind in a chaotic state, and the weary explorer is now ready to return to the creature comforts of the hotel, there to ruminate, and, if he can, arrange in some sort of order, in his “memory’s mansion,” sights and sensations so new and strange. In returning to the upper world, the appearance of the mouth is very beautiful. To eyes so long accustomed to darkness, the light is a subdued radiance, a fairy land in the distance, until we emerge from the cave into the outer world, which seems, since we left it, to have been dyed in millions of rainbow hues; everything, the leaves, the trees, shone and sparkled in the blessed light! But—the air! the pure atmosphere we have been breathing all the morning, renders the senses painfully conscious of the decomposition of vegetable matter, causing such a feeling of oppression that fainting may be the consequence if issuing from the entrance is not made a matter of easy stages.
As a result of the wise maxim,
“Early to bed and early to rise,” we find ourselves on the following morning breakfasting in our cave dress, and prepared before nine o’clock for the “Long Route.”
We now feel quite at home in the under-world, and, should any stranger join our party, he would doubtless be much impressed by our manner of going over the familiar ground; evidently we know all about this; nothing can impress us now but “fresh fields and pastures new.” On this day we are to realize something of the geography of the cave, therefore a word on the subject of its formation.
Green River, only a few hundred yards from the entrance of the cave, has evidently cut out the channel through which it runs. On either side, its rugged banks tower above the water three hundred feet, and this the only valley of the plain, proving conclusively that the river has excavated its bed to the present level by the chemical and mechanical agency of water. The avenues of the cave, no doubt, were cut through in the same manner, the lowest and last formed being Echo and Roaring rivers, which are now on a level with Green River, and with which they have subterraneous communication.[126] As Green River deepens the valley through which it passes, the rivers in the cave will also continue to descend, until the avenues through which they now flow shall become as dry as Marion Avenue, which, in ages past, must have been the most beautiful of subterranean rivers.
Limestone, or carbonate of lime, which constitutes the strata of rocks
through which the cave runs, is soluble in water when it combines with an additional proportion of carbonic acid, and is changed into the bicarbonate of lime.
In this way the process of excavation continued until communication with running water was established, and the mechanical agency made to assist the chemical. Another disintegrating power is the crystallization of sulphate of lime, known also under the names of gypsum, plaster-of-Paris, alabaster, etc. The force of gypsum in the act of crystallizing is equal to that of water in freezing, and, when it occurs between ledges of rock, they are fractured in every direction. Many instances of this may be seen.