The case marked 58 contains the varieties of Fluorides, or combinations of fluorine and the metals. These include the fluoride of calcium, of which the most familiar variety to Englishmen is that known as Derbyshire spar, of which many useful articles are manufactured in this country. Ladies particularly will halt with interest before the case marked 58 A, where the fluorides, better known as the topaz, are deposited. These include a fine series of crystals from the Brazils, Siberia, and Saxony. The 59th case is covered with Chlorides, or combinations of chlorine with other substances, including rock salt, or chloride of sodium; sal-ammoniac from Vesuvius; fine chloride of copper, exhibiting beautiful crystals; and chlorides of silver and mercury. The two last cases in the room (60 and 60 A) contain samples of coal, bitumen, resins, and salts. Here will be found the honey-stone of Thuringia; crystals of phosphate of magnesia and ammonia called struvite; beautiful specimens of amber, some pieces of which inclose insects; and copal, also containing insects; fossil copal; mineral pitch, from naphtha to asphalt; the elastic bitumen of Derbyshire, exhibiting its different degrees of softness; Humboldt's dapèche, an inflammable fossil of South America; and brown and black coal. Having noticed all these varieties, the visitor should advance at once westward into the second room of the mineralogical gallery. Here, against the southern wall, are groups of FOSSIL ANIMALS ranged inside and upon the top of the wall cases. The most remarkable of the remains inclosed in the wall cases of this room are the remains of the carapace and other portions of the gigantic Fossil Tortoise from the Sewalik Hills, Bengal, discovered by the enterprising Major Cautley; and the gigantic fossil bones of an extinct genus of birds that inhabited New Zealand in the remote past. But these wall cases are mainly devoted to the exhibition of chelonian, or tortoise fossils, which are the highest class of fossil reptiles, except the serpents, and found only in the later or oolite formations of the earth. The regularity with which the various families of reptiles are discovered in the earth's strata, according to their order, is remarkable. First the Lizards are found in the magnesian limestone, immediately above the coal deposit, indicating their early appearance on the earth; the next deposit, or new red sandstone, introduces us to the Frogs; the oolite to the Tortoises; and the recent tertiary strata to the Serpents. The bones of the tremendous wingless birds, which are deposited in the third case of this room, have been recognised by Professor Owen as the remains of an animal that must, when living, have stood eleven feet high. By the windows in the northern wall of the room are deposited the beautiful crystallised mass of Selenite, or sulphate of lime, found in the duchy of Saxe Coburg, and presented to the museum by Prince Albert; and a mass of carbonate of lime,