COLOSSAL CAVERN, a limestone solution cave in Edmon son county, central Kentucky, U.S.A., i i m. from the famous Mammoth cave with which it is probably connected. Eden valley, which lies between these caves, is indisputably a `.sink" formed by the collapse of a great chamber or series of chambers that formerly united them. Bed Quilt cave as well as many smaller caverns and grottoes in the vicinity are doubtless part of the same system of caverns, all hollowed out by solution in the St. Louis limestone beneath the overlying Chester sandstone. From the main entrance at the foot of a steep hill across Eden valley from Mammoth cave, the cavern extends southward by the "Chinese Wall," "Uncle Tom's Pool" and "Lizard Spring" to Vaughan's Dome, a great chamber 4o ft. wide, 30o ft. long and 79 ft. high, thence southward by Florence Avenue and the "Ruins of Carthage," a spacious hall 400 ft. long, I oo ft. wide and 3o ft. high of which the flat roof is one continuous limestone block to the so-called "Ruins of Martinique," where the general course changes south-eastward, and passing by a number of spectacular features, leads to Colossal Dome, the most impressive of all the chambers, fringed by innumerable tinted stalactites and stalag mites, richly resonant when struck. Continuing south-eastward past the "Pearly Pool" of limpid water, and by a passageway be tween stately columns and grotesque figures, the cavern ends in a copious chalybeate spring. The fauna of the cavern is character ized by paucity of species, though of these the number of indi viduals is relatively large. The temperature is uniformly 54° F., the atmosphere fresh and pure. (W. E. E.)