CAVE, or CAVERN (OF. care, coins, from Lat. caveat, cave, from Lat. earns, hollow, Gk. tamp, kyar, hole, from silly, kycin, to swell, to contain). A hollow place in the earth's crust. Aside from the subterranean excavations made by man, caves are produced by the fracture and dislocation of strata during periods of upheaval, by the action of water. or by both causes com bined. The eroding and dissolving power of water has formed caverns along river-cow:sea and on seacoasts. The moving waters enter natural crevices and enlarge them by the abrasive action of the suspended sand and gravel. or they attack the softer portions of the strata and form cavities that are inclosed by the more indurated rack. Wave-action is a prominent agency in this process. Caves most frequently occur in limestone regions. where they are usually the result of the solvent action at water and the contained chemical agents, such as carbon dioxide and humic acid. The surface waters in percolating downward through the joint fissures and along the planes of stratifica tion enlarge the channels by solution. Rivers sometimes plunge into the eaves through openings known as sink-hip/es. In some limestone regions, as portions of Kentucky and Florida, these holes are a marked surface caves are of enormous size. The celebrated cave of Fran conia in Germany. that of Kirkdale in Yorkshire, the Mammoth Cave tq•v•) of Kentucky, and Luray Caverns of Virginia, as well as many (Alters. are well known. Rock formations con taining beds of salt, a material easily removed by water, may also abound in caverns. They are also frequently met with in igneous rocks— the picturesque cave of Fingal, in Staffa, is formed in basalt: and in South America and Ice land the recent lava contains large caverns.
Many caverns have a calcareous incrustation lining their interior, giving them a gorgeous appearance. ?ometimes this deposit is pure white, and has, when the cave is lighted up, a richness and transparency that cannot be imag ined. It is. however. more generally colored by the impurities which the water has taken up from the superincumbent strata. To the in crustations which are suspended from the roof, like icicles, the name stalactite is given, while those rising from the floor are designated stal agmites. Sometimes the pendent stalactite is produced so as to meet the ascending stalagmite and form pillars, as if to support the roof, as in the 'organ' in the Blue John Mine, Derbyshire, and the columns of the Cave. The source and origin of this deposit has been satis factorily explained by Liebig as follows: "The mold of the superficial soil. being acted upon by moisture and air, evolves carbonic acid, which is dissolved by rain. The rain-water thus im
pretmated, permeating the calcareous strata. has the power of taking up a portion of the lime, which it retains in a liquid condition. until from evaporation the excess of carbonic acid is parted with, when the lime again returns to its solid state, and forms the incrustation." Caves have an additional interest to the geologist, from the occurrence in many of ani mal remains under the calcareous incrustations of the floor. The bones are imbedded in mud, and frequently concreted into a firm calcareous breccia. They belong to the Pleistocene period, when the caves apparently were inhabited by large hyenas and hears. Portions of other ani mals inhabiting the neighborhood were dragged by these into their dens to serve as food. In this way the bones of herbivorous, and other ani mals are found mixed with those of the beasts of prey: they have a broken and gnawed ap pearance, similar to that produced on recent hones by the teeth of a hyena. No less than thirty-three species of IllaIDDIals five species of birds have been discovered in the caves of the British islands, of which number about half still survive in Europe, while the remainder are ex tinct. The mammals are species of ox, deer, horse, wolf. dog, hare, fox, weasel, water-rat, mole, bat, hippopotamus, and rhinoceros, besides the hyena and boar; and the birds are species of lark, partridge, pigeon, goose, and crow. In the Causses region of southern France there are many caves in .1urassie limestone containing bones of the cave-bear and of human beings, and im plements. The most productive bone-ca VC in Britain is that of Kirkdale, 25 miles from York, in which the remains of about 300 hyenas have been detected. besides innumerable gnawed bones of other animals on which they have preyed. The Carboniferous limestones of Gla morga nsli ire abound in eaves which have been explored by Bucklands and more recently and thoroughly by . .
Dr. Falconer. Ossiferous caves occur in all parts of the globe. The fossils of those in Australia show that the fauna of the Pleistocene period had a remarkable resemblance to that of the present day. The remains consist chiefly of kangaroos and allied genera of marsupials. In Colorado, near Colorado Springs, the bones of the goat, antelope, and woodchuck have been found in limestone caverns. The average tem perature of some caves is so low that ice remains throughout the entire year. Consult: Badin, Grottes et curvy-nes (Paris, 1S70) ; Hovey, relr. bratcd American Caverns (Cincinnati, 1SS2); Browne, Ire Cares of France and Switzerland (London, IS65).