Monthly microscopical journal: transactions of the Royal Microscopical Society, and record of histological research at home and abroad . Polarized light, x —Epidote and calcspar, Quenast, X —Liquid cavities containing crystals of Na CI enclosed in quartz, Quenast. The prismatic crystals are tourmaline. X —Crystal of labrador fractured and bent by fluidal structure in gabbro, Hozeraont, x —Diallage in gabbro, Hozemont, showing the cleavages of that mineral, X —Diallage surrounded by fibrous hornblende, x and 8.—Ilmenite, covered in some parts by its characteristic
Monthly microscopical journal: transactions of the Royal Microscopical Society, and record of histological research at home and abroad . Polarized light, x —Epidote and calcspar, Quenast, X —Liquid cavities containing crystals of Na CI enclosed in quartz, Quenast. The prismatic crystals are tourmaline. X —Crystal of labrador fractured and bent by fluidal structure in gabbro, Hozeraont, x —Diallage in gabbro, Hozemont, showing the cleavages of that mineral, X —Diallage surrounded by fibrous hornblende, x and 8.—Ilmenite, covered in some parts by its characteristic white coating, in gabbro of Hozemont, x —Fragments of crystals of plagioclase and quartz, surrounded by 8ericite in the elastic Porphyroid of Pitet. Polarized light. X 120. * Mem. sur les Caracteres Mineralogiques et Stratigraphiques des Roches ditesPlutouiennes de la Belgique et de IArdenne Fran9aise, par Ch. de la VallecPoubsin et A. Renard, , t. xl. des Mem. Couronnes de IAcademie do work, which is now in the Press, will soon appear. The Monthly Microscopical JouTnal Mayl. 1876 PI. Microscopical Study of the Belgian Rocks. Bij A. Renard. 213 angles are not perfectly sharp ; and, what is very remarkable, thelines which lie perpendicular to the polysynthetic lamellae runclear through, without any break at the point where they intersectthe striae (Fig. 1). In this diorit the microscope has enabled us to prove the pre-sence of orthoklas, a result to which we have been led by the phe-nomena of polarized light, just as is observed in the twin crystals ofCarlsbad. We need not stop to describe the microscopic details ofthe hornblende, which is generally much altered and often sur-rounded by an opaque zone in a state of decomposition, which hasalso obliterated the cleavages. This mineral often contains apatite,and this we consider to have been formed simultaneously with thehornblende; it is also intimately associated wit
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