most charming language of the ruins of Palmyra; and Pliny informs us that the art of cutting marble into slabs dates back to the building of the palace of Mausolus at Halicarnassus. The walls of that celebrated building, one of the seven wonders of the world, were of brick, covered with Cyzican marble from Proconnesus.

This art was introduced into Rome, and the described mode of cutting, by the use of strips of iron and sand, does not materially differ from that practiced at the present day.

The same author states that marble began to be used in public buildings in Rome in the Edileship of M. Sacurus. His theater, described by Pliny as "the greatest that has ever been made by the hands of man,' was three stories high. The lower was of marble, supported by three hundred and sixty columns of the same material; the second of glass, and the highest of gilded wood. This building was planned to seat eighty thousand spectators. After this period there was a rivalry as to who should erect the most costly and grand public buildings; interior walls were not only covered with the most costly imported marbles, but the stone was richly sculptured, and even in part painted or gilded. In the time of Nero, a method of inserting spots, or ornamental patches of other marbles, was invented-a sort of Mosaic or inlaid work, very costly and unnatural, but nevertheless much admired.

Then followed a general mania for marbles and rare ornamental stones, which were introduced into private as well as public buildings, and which were sought in every part of the known world.

The first private citizen who covered the entire walls of his house in Rome was Mamurra, who was only satisfied with the costly and rare marble of Carystus and Luna, the modern Carrara. M. Lepidus made the lintels of his house of Numidian marble (Giallo Antico), in the year of Rome 676. A few years later columns of foreign marble were first erected in Rome by L. Crassus, the orator; his house on the Palatine Hill was remarkable for its magnificence. The columns were six in number, and twelve feet in height; they were of Hymettian marble (Carrara).

L. Lucullus, when Consul, introduced into Rome a black marble, which was found on the island of Melos, and named Lucullan marble after him. We are indebted to Pliny for this information.

The following is a list of the rarer and most noted of ancient marbles:

White: Parian, Pentellic, Luna.

Black: Lucullan, Nero Antico.

Red: Rosso Antico, Cottonello.
Green: Verde Antico.

Variegated: Lumachella, Phrygian, Oriental Alabaster or Onyx.

The Parian and Pentellic marbles were pure white, and were considered better than those of Carrara. They are nearly pure carbonate of lime. Parian was found on the Island of Paros, one of the Grecian Archipelago. It could be distinguished by a peculiar luster on the freshly broken surface. The quarries from which this fine marble was obtained are very ancient. Pentellic marble was from Mount Pentellicus, in Attica, ten miles only from Athens. The Parthenon, in that ancient city, was constructed of this stone. Being completed in 438 B. C., it has resisted the destroying hand of time for two thousand three hundred and twenty-four years. Phidias, born four hundred and ninety years B. C., and Praxitales, celebrated Grecian sculptors, both worked on this, the most magnificent of ancient or modern buildings. The Pentellic quarries have been lately reopened.

Luna or Carrara marble is also nearly pure carbonate of lime (98.1 per cent), the usual impurities are clay, pyrites, and quartz. The marble often contains imbedded crystals of quartz, perfectly transparent and doubly terminated, called "Cararra diamonds.' There are a number of varieties of this marble, but the best has a delicate waxy luster which is much admired; there are many fine specimens in the State Museum. The quarries of Carrara are supposed to have been opened by the Romans one hundred years B. C.; they were worked in the time of Julius Cæsar, and more extensively in the time of Augustus, who was called by Livy "the builder and restorer of all the temples." The ancient Etruscan seaport of Luna, eight miles from Carrara, described by Pliny as a noble harbor," is now more than a mile and a half inland, with meadows extending to the shore. Marble was largely used in the construction of this city; large blocks still remain which are supposed to have been the seawall, from a large metal ring found attached to one of them. During the dark ages, Luna having then fallen into decay, was robbed of its marble blocks and columns, which were sent to construct buildings elsewhere. The marble for the Pantheon at Rome was brought from Carrara; this building was erected by Agrippa twenty-six years B. C., and is still in a good state of preservation. The palace and arch in the Via Domizi, and the baths of Caracalla are of Carrara marble. Lucullan black marble was supposed to have been brought from Meroe in Abyssinia; it sometimes showed small spots and veining of white, but the best quality was pure black. A California marble, recently found near Colfax, and numbered 2799 in the State Museum Catalogue, answers very nearly to the description of the Lucullan marble. The "Nero Antico" was also a black marble, said to have been found in Laconia; it was fine-grained and compact, sometimes showing delicate veining of white.

Fragments of "Rosso Antico" marble are frequently found in the ruins of ancient Rome. The locality of the quarry is unknown, but a similar, if not the same, marble has recently been found at Skautari, a village in Greece. It is of a deep blood red color, sometimes inclining to purple, and even rose color; and sometimes clouded with white, black, or purple lines. A fine specimen from ancient Rome may be seen in the State Museum, numbered 6020. This marble was much admired and prized by the ancients. A marble of beautiful rose color has been found in California; it is numbered 5344 in the Catalogue of the State Museum, and is nearly identical with "Rosso Antico." Very little is yet known of its occurrence, but it is likely to be valuable and important. A description has been given elsewhere.

Cottonello marble was found near a town of the same name a short distance north of Rome. It was of many shades of red, but of inferior quality, although somewhat extensively used.

"Verde Antico," or as it is now called in English, "Verde Antique," is not a true marble, but is serpentine combined with carbonate of lime or magnesia. It was much prized by the ancients, and is still extensively used. The color is due to oxide of chrome, and as chromic iron and serpentine are both common and abundant in California, there is reason to hope that this beautiful ornamental stone may yet be found in the State. There are many fine specimens of "Verde Antico" from Italy in the State Museum. "Giallo Antico" was considered one of the most valuable and beautiful of the ancient marbles. The grain was very fine, and the coloring beautiful and rich. It resembled the Sienna and Verona marbles, but exceeded them in beauty and texture. It was first found in Numidia, in Northern Africa, and for that reason sometimes called "Numidian marble." It

received a high polish. The base or keynote color was yellow of many shades, from the deepest to nearly white or pale straw color. Some varieties were brecciated, and others veined or mottled.

There are a number of examples of this marble still to be seen in Rome; columns at the Pantheon, the Arch of Constantine, and two columns at the Vatican. An ancient quarry has lately been discovered in Algiers, which is supposed to be that worked by the Romans, and afterwards abandoned and lost.

A beautiful yellow brecciated marble has been found at Tehachapi in Kern County, California, which resembles some of the described varieties of "Giallo Antico." It is certainly very beautiful. It is numbered 710 in the State Museum Catalogue. Another mention of this beautiful marble is made elsewhere.

Sienna marble, found near Volterra, is from cream color to dark yellow, sometimes veined with white, and even black. It is much employed at the present time, and is a durable and beautiful ornamental stone.

Nummulitic, or Verona marble, is in color from cream to nearly white. It was much used in ancient and mediæval buildings; the Roman amphitheater of Diocletian was built of it. It was extensively used in Venice; the porch and interior columns of the cathedral of Verona are fine examples. Lumachello, or "fire marble," owes its wonderful brilliancy and play of colors to imbedded shells; it is now found at Bleiberg in Carinthia.

The Phrygian marble was very rare and costly; the ground color was creamy white, with veins of dark red, sometimes pink, or yellow. From its fancied resemblance to the plumage of the peacock, it was sometimes called "Pavonazetta." The Emperor Hadrian was very fond of it, and it was used in the construction of his tomb. The temples of Juno and Jupiter had one hundred and twenty columns, and a pillar of it was found in the ruins of Pompeii.

Oriental alabaster or onyx marble was held in high esteem by the ancients a thousand years or more ago. The quarries were lost, and for a long time remained unknown, until rediscovered in Egypt in 1849, by M. Delmonte, a French traveler. The marble of the same nature found in California and known as Suisun marble," and "California onyx," is more beautiful in some of its varieties than the ancient, and it has gained a world wide reputation for beauty. In the fourth annual report of this office, on folio 72, this beautiful ornamental stone has been described, and the principal locality given. Attention has only lately been called to the marbles of our State, and while few fine varieties are known, many more will doubtless be found. There is reason to believe that there will soon be an awakening in our State and principal cities to the importance of this subject, and in time our mountains, now so celebrated for the vast quantities of gold they have given to the world, will be searched over for building materials, and the fortunate person who discovers a quarry of good building stone or marble, will be more sure of a fortune than the gold seeker who now prospects the heights for the precious metals. In anticipation of this, new localities have been recorded in these reports, and discoveries already made. It will be seen that during the few years of the duration of the State Mining Bureau, that something has been accomplished in this direction.

TECHNICAL DESCRIPTION OF THE RED MARBLE (ROSEO ANTICO), FOUND IN AMADOR COUNTY, MENTIONED ABOVE.

Color, blood red, with mottlings of a slightly different shade, and an occasional vein of pure white. Specific gravity, 2.828; hardness, 3. By

qualitative analysis it was found to contain lime, carbonic acid, oxide of iron, and silica.

It dissolves with violent effervescence in hot hydrochloric acid, leaving a small red insoluble residue. The filtrate was golden yellow; ammonia threw down a heavy precipitate, leaving a transparent and colorless liquid, in which oxalate of ammonia caused a heavy precipitate of lime. This filtered off, phosphate of soda gave no precipitate, but the filtrate became slightly opalescent.

A few fragments of the marble, heated to redness in a platinum crucible, lost 14 per cent by weight. The residue was nearly white. It slaked and became hot on addition of water, but still contained carbonic acid, and effervesced slightly with hydrochloric acid. When dissolved and the residue dried on a water bath, a considerable portion was found to be magnetic. The non-magnetic portion looked, when seen under the microscope, like selenite, or more like brucite.

A sample treated in powder with cold diluted hydrochloric acid, left a large red residue, 9.4 per cent, and the solution was colorless. The red residue was partly soluble in boiling hydrochloric acid. Fused with alkaline carbonates it became decomposed, and was then soluble in hydrochloric acid, leaving a residue of silica, equal to 3.74 of the marble. The solution containing sesqui-chloride of iron was golden yellow; ammonia precipitated all the iron, leaving the solution colorless.

The yellow brecciated Tehachapi marble, from Kern County; the California giallo antico, mentioned above, was also examined chemically. It effervesced with acids and was nearly all soluble, the insoluble portion being only 1.6 per cent. From the solution carbonate of soda threw down a precipitate weighing 92 per cent.

Mr. Israel Luce, of Sacramento, called April 20, 1886, at the State Mining Bureau, and gave the following information regarding the locality of this marble.

The deposit is a large one, and is situated half a mile from the town of Tehachapi, on the road to Caliente. At that distance, on a flat on which there are springs of water, stands a small house. Less than a quarter of a mile from the house, up the hill, by an old wagon road, the excavations may be seen, and some large blocks lie quarried out. Mr. Luce says that some of the marble is of a pure yellow color and very beautiful.

TEHACHAPI MARBLE (not Giallo Antico).

Mr. W. G. Campbell called April 23, 1886, at the State Mining Bureau and informed me that the so called Tehachapi marble is found nine miles west of the town of Tehachapi, in Bright's Valley. It is found in large quantities, and there is a large block at the railroad station at Tehachapi. The marble is fine grained and beautifully mottled, resembling specimen No. 5860 of the museum catalogue.

The beautiful recently discovered Humboldt marble is found on the lumber claim of Flanegan & Brosman, seven miles from Eureka. This is all the information this office has concerning it.

DOLOMITE.

Dolomite is a double carbonate of lime and magnesia, sometimes in chemical equivalents, sometimes in mechanical mixture. It is called by many names, as dolomite, magnesian limestone, bitter spar, magnesian spar,

pearl spar, brown spar, compound spar, rhomb spar, muricalcite, picrite, tharandite, miemite, conite, gurhofian, and, lastly, Inyo marble.

It is considered true dolomite when in chemical proportions, otherwise magnesian limestone. Its hardness is from 3-5 to 4; specific gravity, 2-9; weight of cubic foot, about 180 pounds; luster, from vitreous to earthy; color, white, various shades of rose red, gray, brown, green, or nearly black. The composition is so varied that no single analysis would convey a correct idea; when expressed by the formula, Ca O, CO2+MgO CO2, it contains

Carbonate of lime..

Carbonate of magnesia.

54.35

45.65

100.00

In Klaproth's Chemical Mineralogy, published in English in 1801, may be found detailed analyses of two specimens, one from Sweden, and the other from the Tyrol, since which time very many analyses have been made and published. Before 1791 dolomite was confounded with the limestones, until the celebrated French chemist and mineralogist, Dolomieu, called attention to it. He first noticed it among the remains of ancient sculpture in Rome. In a paper to the Journal of Physics, he described it under the name of "A calcareous stone which effervesces but little with the acids." Saussure, a Swiss naturalist, found it in place in the Alps, and named it after the original discoverer "dolomie." The present name, "dolomite," was given to it in 1794 by Kirwan, an Irish chemist and mineralogist.

Dolomite was originally a sedimentary rock; this is proved by the fossils it often contains. There are several theories as to its formation, but the chemistry of its genesis is admitted to be very imperfectly understood. One theory is that it was formed in the beds of large lagoons, which became inland seas by being cut off from the ocean by some geological change in the earth's surface. As the confined water slowly evaporated, it dropped its lime, its salt, and lastly its magnesia, forming beds of dolomite. This theory is supported by the fact that beds of clay, gypsum, and rock salt are frequently found associated with dolomite. Another theory is that it was originally a precipitate let fall from the primitive sea by supersaturation, as thinolite is now being and has been formed in the alkaline lakes of the Great Basin of California, Nevada, and Utah. Still another theory assumes that the deposit was originally limestone, formed at the bottom of an ancient ocean, and that metamorphism has taken place by the addition of carbonate of magnesia from concentrated sea water, or by the abstraction of a portion of the lime by the action of water holding carbonic acid from a mineral or rock already containing a notable quantity of carbonate of magnesia. Dolomite has been formed artificially in several instances. Once in a glass flask containing a mineral water, which held bi-carbonate of lime and magnesia in considerable quantity, crystals of dolomite formed from two to three millimeters long.

Morlot produced dolomite crystals by heating carbonate of lime with solution of sulphate of magnesia in a closed tube.

Durocher subjected fragments of porous limestone in a bed of chloride. of magnesium for three hours in a gun barrel kept at a red heat. Dolomite crystals formed which were stained yellow by iron. Other successful experiments of a similar nature have been recorded.

Dolomite has been used in sculpture, in architecture, and for making lime and cement. In the United States lime made of it is held in esteem,