BASALT'S.
According to Strabo and Agricola, the antique basaltes is found in the same pris matical form in Egypt, which distinguish_ es its outline in various parts of Europe. Farber, a professor of natural history at Mietau, supposes that found in the Vi centine Paduan and Veronese districts of Italy to be a crystallized lava, and as serts, that the antique bushes is in every respect exactly similar to the compact lavas of Vesuvius and Monte Albano, which are used by statuaries to restore mutilated statues made of this material.
The Egyptian basaltes contain a small proportion, in some of the varieties, of the white garnet like short crystallizations and lamellas common in the Italian lavas, a circumstance that seems to prove to demonstration their volcanic production in these partibular instances, though others of the oriental basaltes seem to have originated from aqueous mix tures.
Dr. Von Troil, member of the Acade my of Sciences at Stockholm, entertained an opinion that they were caused by the operations of fire, which he founded on that of M. Desmaret, who was the first naturalist that ventured to attribute them to that cause, in a description of some basaltes, found near St. Sandour, in Au vergne, presented by him to the atten tion of the French Academy of Sciences. Other naturalists, who had considered them to be a species of crystallization, ridiculed this idea as founded upon false principles, as they contended basalt pil lars are discovered where it seemed highly improbable that volcanoes could ever have existed ; still, however, they had the candour to enter into an ex amination of the assertion of M. Des maret, the result of which was nearly a confirmation of his conjecture, that basalt pillars were produced by subter-' raneous fires. As a collateral support of this hypothesis, Dr. Von Troil cites the instances of Stolpenstein in Meissen, Lauban in Lusatia, of Bohemia, Leignitz in Silesia, Brandau in Beni*, Sicily, Bolsenna, Montebello, and St. Forio in Italy ; the district of Vicenza, Monte Rosso, in the District of Padua, Monte Diavolo in the mountains of Verona, in Lower Languedoc, in Ireland, and in the western island; of Scotland, in each of which places, he says, a doubt cannot be entertained that volcanoes have existed; besides those, he mentions St. Giovanni,
Monte Castillo, Monte Nuovo, Monte Oliveta, near Cader Idris, in Wales, and almost every part of Velay and Auvergne, where the towns of Chillac and St. Fluor are situated upon basaltes.
The peasantry of Iceland seem to have entertained a similar opinion of their ori gin to that of the lower orders of the Irish, as the former suppose them to have been piled, in the regular manner they are seen there, by giants, and thence call them Trollahland and Trollkonugardur, and the latter term their magnificent causeway, t he Giant's. The pillars of the Icelandic basaltes have generally from three to seven sides ; they vary in thick ness from four to six feet, and some of thirty-six, and others even forty•i...ght feet in length, without horizontal divi sions ; but such are the capricious opera tions of nature, that pillars are sometimes.
found not more than six or twelve inches long ; those, however, are invariably very regular, and are made use of for doors and windows ; at others they appear in the utmost confusion, broken, and over turned ; in particular instances they just appear above the surface of the moun tains, amongst lava and tufty and there are places where they extend three miles together without interruption. The ba salt pillars of Glockenberg in Snefialds nes, exhibit a very different appearance from those of any other part of Iceland, as the pillars on the summit of that moun tain lie horizontally, those on the sides incline, and the lowest stand erect. In some places they are found as if bent, When heated, into a semicircular form, an effect which seems to confirm the idea that violent fires have prevailed, either at their formation, or subsequently.