Volcanic Islands [85]
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.
Robert, M., on strata of Iceland.
Rogers, Professor, on curved lines of elevation.
Salses, compared with tuff craters.
Salt deposited by the sea. -in volcanic strata. -lakes of, in craters.
Sandstone of Brazil. -of the Cape of Good Hope. -platforms of, in New South Wales.
Schorl, radiating.
Scrope, Mr. P., on laminated trachyte. -on obsidian. -on separation of trachyte and basalt. -on silex in trachyte. -on sphaerulites.
Seale, Mr., geognosy of St. Helena. -on dikes. -on embedded birds' bones.
Seale, on extinct shells of St. Helena.
Sedgwick, Professor, on concretions.
Septaria, in concretions in tuff.
Serpulae on upraised rocks.
Seychelles.
Shells, colour of, affected by light. -from Van Diemen's land. -land, extinct, at St. Helena. -particles of, drifted by the wind at St. Helena.
Shelly matter deposited by the waves.
Siau, M., on ripples.
Signal Post Hill.
Silica, deposited by steam. -large proportion of, in obsidian. -specific gravity of.
Siliceous sinter.
Smith, Dr. A., on junction of granite and clay-slate.
Spallanzani on decomposed trachyte.
Specific gravity of recent calcareous rocks and of limestone. -of lavas.
Sphaerulites in glass and in silicified wood. -in obsidian.
Sowerby, Mr. G.B., on fossil-shells from Van Diemen's land. -from St. Jago. -land-shells from St. Helena.
St. Helena. -crater of elevation of.
St. Jago, crater of elevation of. -effects of calcareous matter on lava.
St. Paul's rocks.
Stokes, Mr., collections of sphaerulites and of obsidians.
Stony-top, Little. -Great.
Stratification of sandstone in New South Wales.
Streams of obsidian.
Stutchbury, Mr., on marine remains at Otaheite.
Subsided space at Ascension.
Tahiti.
Talus, stratified,
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.
Robert, M., on strata of Iceland.
Rogers, Professor, on curved lines of elevation.
Salses, compared with tuff craters.
Salt deposited by the sea. -in volcanic strata. -lakes of, in craters.
Sandstone of Brazil. -of the Cape of Good Hope. -platforms of, in New South Wales.
Schorl, radiating.
Scrope, Mr. P., on laminated trachyte. -on obsidian. -on separation of trachyte and basalt. -on silex in trachyte. -on sphaerulites.
Seale, Mr., geognosy of St. Helena. -on dikes. -on embedded birds' bones.
Seale, on extinct shells of St. Helena.
Sedgwick, Professor, on concretions.
Septaria, in concretions in tuff.
Serpulae on upraised rocks.
Seychelles.
Shells, colour of, affected by light. -from Van Diemen's land. -land, extinct, at St. Helena. -particles of, drifted by the wind at St. Helena.
Shelly matter deposited by the waves.
Siau, M., on ripples.
Signal Post Hill.
Silica, deposited by steam. -large proportion of, in obsidian. -specific gravity of.
Siliceous sinter.
Smith, Dr. A., on junction of granite and clay-slate.
Spallanzani on decomposed trachyte.
Specific gravity of recent calcareous rocks and of limestone. -of lavas.
Sphaerulites in glass and in silicified wood. -in obsidian.
Sowerby, Mr. G.B., on fossil-shells from Van Diemen's land. -from St. Jago. -land-shells from St. Helena.
St. Helena. -crater of elevation of.
St. Jago, crater of elevation of. -effects of calcareous matter on lava.
St. Paul's rocks.
Stokes, Mr., collections of sphaerulites and of obsidians.
Stony-top, Little. -Great.
Stratification of sandstone in New South Wales.
Streams of obsidian.
Stutchbury, Mr., on marine remains at Otaheite.
Subsided space at Ascension.
Tahiti.
Talus, stratified,