Juan Fernandez. Keilhau, M., on granite. Kicker Rock. King George’s sound. Labrador feldspar, ejected. Lakes at bases of volcanoes. Lamination of volcanic rocks. Land-shells, extinct, at St. Helena. Lanzarote, calcareous beds of. Lava, adhesion to sides of a gorge. -feldspathic. -with cells semi-amygdaloidal. Lavas, specific gravity of. Lava-streams blending together at St. Jago. -composition of surface of. -differences in the state of their surfaces. -extreme thinness of. -heaved up into hillocks at the Galapagos archipelago. -their fluidity. -with irregular hummocks at Ascension. Lead, separation from silver. Lesson, M., on craters at Ascension. Leucite. Lime, sulphate of, at Ascension. Lonsdale, Mr., on fossil-corals from Van Diemen’s land. Lot, St. Helena. Lyell, Mr., on craters of elevation. -on embedded turtles’ eggs. -on glossy coating to dikes. Macaulay, Dr., on calcareous casts at Madeira. MacCulloch, Dr., on an amygdaloid. -on chlorophaeite. -on laminated pitchstone. Mackenzie, Sir G., on cavernous lava-streams. -on glossy coatings to dikes. -on obsidian streams. -on stratification in Iceland. Madeira, calcareous casts at. “Magazine, Nautical,” account of volcanic phenomena in the Atlantic. Marekanite. Mauritius, crater of elevation of. Mica, in rounded nodules. -origin in metamorphic slate. -radiating form of. Miller, Prof., on ejected Labrador feldspar. -on quartz crystals in obsidian beds. Mitchell, Sir T., on bombs. -on the Australian valleys. Mud streams at the Galapagos archipelago. Narborough island. Nelson, Lieut., on the Bermuda islands. New Caledonia. New Red sandstone, cross cleavage of. New South Wales. New Zealand. Nulliporae (fossil), resembling concretions. Obsidian, absent at the Galapagos archipelago. -bombs of. -composition and origin of. -crystals of feldspar sink in. -its irruption from lofty craters. -passage of beds into. -specific gravity of. -streams of. Olivine decomposed at St. Jago. -at Van Diemen’s land. -in the lavas at the Galapagos archipelago. Oolitic structure of recent calcareous beds at St. Helena. Otaheite. Oysters, extinction of. Panza islands, laminated trachyte of. Pattinson, Mr., on the separation of lead and silver. Paul’s, St., rocks of. Pearlstone. Peperino. Peron, M., on calcareous rocks of Australia. Phonolite, hills of. -laminated. -with more fusible hornblende. Pitchstone. -dikes of. Plants, extinct. Plutonic rocks, separation of constituent parts of, by gravity. Porto Praya. Prevost, M. C., on rarity of great dislocations in volcanic islands. Prosperous hill, St. Helena. Pumice, absent at the Galapagos archipelago. -laminated. Puy de Dome, trachyte of. Quail island, St. Jago. Quartz, crystals of, in beds alternating with obsidian. -crystallised in sandstone. -fusibility of. -rock, mottled from metamorphic action with earthy matter. Red hill. Resin-like altered scoriae. Rio de Janeiro, gneiss of.