All these wonderful plays of Nature, in which form and colour contribute to delight the eye or to charm the fancy of the spectator, are, however, still less interesting than the reflections suggested by the slow growth of stalactites in general, and the enormous size which some of them attain. [Illustration: STALACTITAL CAVERN IN AUSTRALIA.] Inscriptions seventy or eighty years old appear covered only with a thin translucent coat of sinter, and in the Cave of Adelsberg names scratched in the walls more than six centuries ago are still perfectly legible. How many ages must, then, have passed before such colossal stalagmites could have been formed as, for instance, in the Australian cavern explored by Mr. Woods,[13] or in the Cave of Corneale, near Trieste, where we find one of these formations measuring fifty feet in circumference, and another rising thirty-five feet above the ground, with a trunk as massive as that of an old oak. The ruins of Thebes, or the rock-temples of Ipsamboul, appear almost as works of the present day when compared with those amazing monuments of time. But, while meditating on their colossal dimensions, the mind is necessarily carried still further back, and wanders through the countless ages which the filtering waters, collecting into subterranean streams, required for hollowing out the vast cavities on whose floor those gigantic stalagmites were subsequently deposited. An epoch of still older date presents itself when the limestone rocks, now pierced with vast stalactital caverns, were first slowly forming at the bottom of the primeval sea by the accumulation of countless exuviæ of zoophytes, star- fishes, and foraminifera, and after growing into strata many hundred feet thick, were then forced upwards by plutonic powers, and became portions of the dry land. Nor is this the end of the vast perspective, for changes still more remote loom in the fathomless distance. The mind grows giddy while thus plunging into the abyss of time, and, in spite of the ideas of sublimity awakened by such meditations, feels a painful sense of its incapacity to conceive a plan of such infinite extent. Footnote 13: ‘The Geology of South Australia.’