tions. In the azoic group it is a metamorphic rock of granular and crystalline structure, and often presents a fineness of texture and purity of shading that fit it for the choicest works of the sculptor. In the palæozoic formations it bears more of the character of a sedimentary rock, and it is apt to contain organic vestiges, as corallines and fossil shells, which indeed sometimes compose nearly its whole substance; it is also of variegated colors, and sometimes is of brecciated structure, evidently made up of fragments of an older rock, the layers of which, broken up and confusedly rearranged, have been cemented together. Though thus varying greatly in color, texture, and structure, the composition of marble is for the most part essentially the same; it is a carbonate of lime, or a combined carbonate of lime and carbonate of magnesia, and is readily burned to quick-lime. It is soft and easy to work with the chisel or hammer, generally of even grain, so as to be split with wedges, and of specific gravity about 2.7, making the weight of a cubic foot about 169 lbs. Its durability is very variable, some varieties retaining sharp edges when exposed for many years to the weather, and others soon crumbling away.—Many varieties of marble have acquired a name and celebrity from remote times. The ease with which the rock is worked caused it to be selected for the earliest structures. The names of many marbles famous among the ancient Greeks and Romans are still retained, and their localities are known. Mt. Pentelicus in Attica furnished the valuable Pentelican white marble, called by the moderns Penteli marble; the islands of Paros and Naxos, the still celebrated Parian marble; and other similar white marbles came from Mt. Hymettus in Attica, from Thasos and Lesbos, from Corallus in Phrygia, from Cyzicus on the Propontis, and one variety, exceeding the Parian in whiteness, from Luna in Etruria. Of the first named (the Pentelican) the Parthenon was built, and also the temple of Ceres at Eleusis, besides many celebrated statues. Though of finer grain than the Parian, it is said not to retain its polish and beauty so well. The Parian marble is placed first by both Theophrastus and Pliny in their enumeration of ancient marbles. Pindar and Theocritus also celebrated its praise. The statues of Venus de' Medici, Diana Venatrix, the Oxford marbles known as the Parian chronicle, and many other famous works, are of this marble. Black marbles are occasionally referred to by the ancients; but some of those named, as the Chium marmor from the island of Chios, appear to be of questionable character. This one is sometimes called lapis obsidianus antiquorum. It was glossy black, and received so high a polish that it was made into mirrors. The green marbles were serpentines from various localities. Yellow marble was obtained at Corinth. The marmor Phengites of Cappadocia was white with yellow spots; the Rhodian was marked with golden-colored spots, and that of Melos (Milo) was yellow.—The marbles of modern times have been variously classified and named. In southern Europe two general divisions are made of antique and modern. The quarries of the former being lost or abandoned, the stone is obtained only from ancient monuments; and being consequently most highly prized, methods are resorted to, and sometimes with success, to attach the name antique to stone from quarries now worked. It is also the case that some of the marbles held in the highest estimation in France, being transported from monuments at Rome, are the product of quarries worked in ancient times in France. It is probable these might be again discovered. Without reference to these marbles, however, the French boast that their country surpasses even Italy in the beauty and variety of this class of stones.—The following are convenient divisions in which marbles may be arranged for a general notice of the most important of them: 1, the simple or single-colored marbles; 2, the variegated; 3, the brecciated; 4, the lumachella or fossiliferous. These sorts, however, pass into each other, so that some may be placed indifferently either in one or the other of two groups. 1. The best known of the first class are the plain white marbles, some of which have been already named. The white marble of Carrara, of which an account is given in the article Carrara Marble, is of a texture like loaf sugar, differing in this respect from the Parian marble, which on close examination appears to be made up of the most delicate plates or scales, confusedly but most closely united together. Pure black marble is found in some ancient Roman sculptures. Some varieties of it are obtained in Derbyshire, England, and in Kilkenny, Ireland; but as the latter is more or less intermixed with fossil shells, it should come under the fourth division. It is quarried in the United States at Shoreham, Vt., and Glen's Falls, N. Y., and specimens are obtained from some other localities. The colored marbles are generally variegated; but the Siena marble of Italy is sometimes of a uniform yellow color, or the same clouded. Some of the red marbles of Italy also display only the one color. In North America white marbles are worked at various places on the range of the great belt of metamorphic rocks through Canada, Vermont, western Massachusetts, a little back of the cities of New York, Philadelphia, Baltimore, and Washington, and thence through Virginia and the Carolinas into northern Georgia and Alabama. It is this formation that supplies the white marble for building purposes to the different cities along its range, and its quarries in Massachusetts and New York furnish the marble for the most costly edifices of southern cities. The statuary marble is only the finest grained variety of this common building stone. Many localities are known to furnish it in small beds interstratified with the coarser marble. Several quarries of fine statuary marble have been opened in Vermont. The first were at Rut-
