Chapter VIII: Northern Chile.—conclusion (3)

Ascending to the older tertiary formations, I will not again recapitulate the remarks already given at the end of the Fifth Chapter,—on their great extent, especially along the shores of the Atlantic—on their antiquity, perhaps corresponding with that of the eocene deposits of Europe,—on the almost entire dissimilarity, though the formations are apparently contemporaneous, of the fossils from the eastern and western coasts, as is likewise the case, even in a still more marked degree, with the shells now living in these opposite though approximate seas,—on the climate of this period not having been more tropical than what might have been expected from the latitudes of the places under which the deposits occur; a circumstance rendered well worthy of notice, from the contrast with what is known to have been the case during the older tertiary periods of Europe, and likewise from the fact of the southern hemisphere having suffered at a much later period, apparently at the same time with the northern hemisphere, a colder or more equable temperature, as shown by the zones formerly affected by ice-action. Nor will I recapitulate the proofs of the bottom of the sea, both on the eastern and western coast, having subsided seven or eight hundred feet during this tertiary period; the movement having apparently been co-extensive, or nearly co-extensive, with the deposits of this age. Nor will I again give the facts and reasoning on which the proposition was founded, that when the bed of the sea is either stationary or rising, circumstances are far less favourable than when its level is sinking, to the accumulation of conchiferous deposits of sufficient thickness, extension, and hardness to resist, when upheaved, the ordinary vast amount of denudation. We have seen that the highly remarkable fact of the absence of any _ extensive_ formations containing recent shells, either on the eastern or western coasts of the continent,—though these coasts now abound with living mollusca,—though they are, and apparently have always been, as favourable for the deposition of sediment as they were when the tertiary formations were copiously deposited,—and though they have been upheaved to an amount quite sufficient to bring up strata from the depths the most fertile for animal life—can be explained in accordance with the above proposition. As a deduction, it was also attempted to be shown, first, that the want of close sequence in the fossils of successive formations, and of successive stages in the same formation, would follow from the improbability of the same area continuing slowly to subside from one whole period to another, or even during a single entire period; and secondly, that certain epochs having been favourable at distant points, in the same quarter of the world for the synchronous accumulation of fossiliferous strata, would follow from movements of subsidence having apparently, like those of elevation, contemporaneously affected very large areas.

There is another point which deserves some notice, namely, the analogy between the upper parts of the Patagonian tertiary formation, as well as of the upper possibly contemporaneous beds at Chiloe and Concepcion, with the great gypseous formation of Cordillera; for in both formations, the rocks, in their fusible nature, in their containing gypsum, and in many other characters, show a connection, either intimate or remote, with volcanic action; and as the strata in both were accumulated during subsidence, it appears at first natural to connect this sinking movement with a state of high activity in the neighbouring volcanoes. During the cretaceo-oolitic period this certainly appears to have been the case at the Puente del Inca, judging from the number of intercalated lava-streams in the lower 3,000 feet of strata; but generally, the volcanic orifices seem at this time to have existed as submarine solfataras, and were certainly quiescent compared with their state during the accumulation of the porphyritic conglomerate formation. During the deposition of the tertiary strata we know that at S. Cruz, deluges of basaltic lava were poured forth; but as these lie in the upper part of the series, it is possible that the subsidence may at that time have ceased: at Chiloe, I was unable to ascertain to what part of the series the pile of lavas belonged. The Uspallata tuffs and great streams of submarine lavas, were probably intermediate in age between the cretaceo-oolitic and older tertiary formations, and we know from the buried trees that there was a great subsidence during their accumulation; but even in this case, the subsidence may not have been strictly contemporaneous with the great volcanic eruptions, for we must believe in at least one intercalated period of elevation, during which the ground was upraised on which the now buried trees grew. I have been led to make these remarks, and to throw some doubt on the strict contemporaneousness of high volcanic activity and movements of subsidence, from the conviction impressed on my mind by the study of coral formations,[19] that these two actions do not generally go on synchronously;—on the contrary, that in volcanic districts, subsidence ceases as soon as the orifices burst forth into renewed action, and only recommences when they again have become dormant.

[19] “The Structure, etc., of Coral Reefs.”

At a later period, the Pampean mud, of estuary origin, was deposited over a wide area,—in one district conformably on the underlying old tertiary strata, and in another district unconformably on them, after their upheaval and denudation. During and before the accumulation, however, of these old tertiary strata, and, therefore, at a very remote period, sediment, strikingly resembling that of the Pampas, was deposited; showing during how long a time in this case the same agencies were at work in the same area. The deposition of the Pampean estuary mud was accompanied, at least in the southern parts of the Pampas, by an elevatory movement, so that the M. Hermoso beds probably were accumulated after the upheaval of those round the S. Ventana; and those at P. Alta after the upheaval of the M. Hermoso strata; but there is some reason to suspect that one period of subsidence intervened, during which mud was deposited over the coarse sand of the Barrancas de S. Gregorio, and on the higher parts of Banda Oriental. The mammiferous animals characteristic of this formation, many of which differ as much from the present inhabitants of South America, as do the eocene mammals of Europe from the present ones of that quarter of the globe, certainly co-existed at B. Blanca with twenty species of mollusca, one balanus, and two corals, all now living in the adjoining sea: this is likewise the case in Patagonia with the Macrauchenia, which co-existed with eight shells, still the commonest kinds on that coast. I will not repeat what I have elsewhere said, on the place of habitation, food, wide range, and extinction of the numerous gigantic mammifers, which at this late period inhabited the two Americas.

The nature and grouping of the shells embedded in the old tertiary formations of Patagonia and Chile show us, that the continent at that period must have stood only a few fathoms below its present level, and that afterwards it subsided over a wide area, seven or eight hundred feet. The manner in which it has since been rebrought up to its actual level, was described in detail in the First and Second Chapters. It was there shown that recent shells are found on the shores of the Atlantic, from Tierra del Fuego northward for a space of at least 1,180 nautical miles, and at the height of about 100 feet in La Plata, and of 400 feet in Patagonia. The elevatory movements on this side of the continent have been slow; and the coast of Patagonia, up to the height in one part of 950 feet and in another of 1,200 feet, is modelled into eight great, step-like, gravel-capped plains, extending for hundreds of miles with the same heights; this fact shows that the periods of denudation (which, judging from the amount of matter removed, must have been long continued) and of elevation were synchronous over surprisingly great lengths of coasts. On the shores of the Pacific, upraised shells of recent species, generally, though not always, in the same proportional numbers as in the adjoining sea, have actually been found over a north and south space of 2,075 miles, and there is reason to believe that they occur over a space of 2,480 miles. The elevation on this western side of the continent has not been equable; at Valparaiso, within the period during which upraised shells have remained undecayed on the surface, it has been 1,300 feet, whilst at Coquimbo, 200 miles northward, it has been within this same period only 252 feet. At Lima, the land has been uplifted at least 80 feet since Indian man inhabited that district; but the level within historical times apparently has subsided. At Coquimbo, in a height of 364 feet, the elevation has been interrupted by five periods of comparative rest. At several places the land has been lately, or still is, rising both insensibly and by sudden starts of a few feet during earthquake-shocks; this shows that these two kinds of upward movement are intimately connected together. For a space of 775 miles, upraised recent shells are found on the two opposite sides of the continent; and in the southern half of this space, it may be safely inferred from the slope of the land up to the Cordillera, and from the shells found in the central part of Tierra del Fuego, and high up the River Santa Cruz, that the entire breadth of the continent has been uplifted. From the general occurrence on both coasts of successive lines of escarpments, of sand-dunes and marks of erosion, we must conclude that the elevatory movement has been normally interrupted by periods, when the land either was stationary, or when it rose at so slow a rate as not to resist the average denuding power of the waves, or when it subsided. In the case of the present high sea-cliffs of Patagonia and in other analogous instances, we have seen that the difficulty in understanding how strata can be removed at those depths under the sea, at which the currents and oscillations of the water are depositing a smooth surface of mud, sand, and sifted pebbles, leads to the suspicion that the formation or denudation of such cliffs has been accompanied by a sinking movement.

In South America, everything has taken place on a grand scale, and all geological phenomena are still in active operation. We know how violent at the present day the earthquakes are, we have seen how great an area is now rising, and the plains of tertiary origin are of vast dimensions; an almost straight line can be drawn from Tierra del Fuego for 1,600 miles northward, and probably for a much greater distance, which shall intersect no formation older than the Patagonian deposits; so equable has been the upheaval of the beds, that throughout this long line, not a fault in the stratification or abrupt dislocation was anywhere observable. Looking to the basal, metamorphic, and plutonic rocks of the continent, the areas formed of them are likewise vast; and their planes of cleavage and foliation strike over surprisingly great spaces in uniform directions. The Cordillera, with its pinnacles here and there rising upwards of twenty thousand feet above the level of the sea, ranges in an unbroken line from Tierra del Fuego, apparently to the Arctic circle. This grand range has suffered both the most violent dislocations, and slow, though grand, upward and downward movements in mass; I know not whether the spectacle of its immense valleys, with mountain-masses of once liquified and intrusive rocks now bared and intersected, or whether the view of those plains, composed of shingle and sediment hence derived, which stretch to the borders of the Atlantic Ocean, is best adapted to excite our astonishment at the amount of wear and tear which these mountains have undergone.

The Cordillera from Tierra del Fuego to Mexico, is penetrated by volcanic orifices, and those now in action are connected in great trains. The intimate relation between their recent eruptions and the slow elevation of the continent in mass,[20] appears to me highly important, for no explanation of the one phenomenon can be considered as satisfactory which is not applicable to the other. The permanence of the volcanic action on this chain of mountains is, also, a striking fact; first, we have the deluges of submarine lavas alternating with the porphyritic conglomerate strata, then occasionally feldspathic streams and abundant mineral exhalations during the gypseous or cretaceo-oolitic period: then the eruptions of the Uspallata range, and at an ancient but unknown period, when the sea came up to the eastern foot of the Cordillera, streams of basaltic lava at the foot of the Portillo range; then the old tertiary eruptions; and lastly, there are here and there amongst the mountains, much worn and apparently very ancient volcanic formations without any craters; there are, also, craters quite extinct, and others in the condition of solfataras, and others occasionally or habitually in fierce action. Hence it would appear that the Cordillera has been, probably with some quiescent periods, a source of volcanic matter from an epoch anterior to our cretaceo-oolitic formation to the present day; and now the earthquakes, daily recurrent on some part of the western coast, give little hope that the subterranean energy is expended.

[20] On the Connection of certain Volcanic Phenomena in South America: “Geolog. Transact.,” vol. v, p. 609.

Recurring to the evidence by which it was shown that some at least of the parallel ridges, which together compose the Cordillera, were successively and slowly upthrown at widely different periods; and that the whole range certainly once, and almost certainly twice, subsided some thousand feet, and being then brought up by a slow movement in mass, again, during the old tertiary formations, subsided several hundred feet, and again was brought up to its present level by a slow and often interrupted movement; we see how opposed is this complicated history of changes slowly effected, to the views of those geologists who believe that this great mountain-chain was formed in late times by a single blow. I have endeavoured elsewhere to show,[21] that the excessively disturbed condition of the strata in the Cordillera, so far from indicating single periods of extreme violence, presents insuperable difficulties, except on the admission that the masses of once liquified rocks of the axes were repeatedly injected with intervals sufficiently long for their successive cooling and consolidation. Finally, if we look to the analogies drawn from the changes now in progress in the earth’s crust, whether to the manner in which volcanic matter is erupted, or to the manner in which the land is historically known to have risen and sunk: or again, if we look to the vast amount of denudation which every part of the Cordillera has obviously suffered, the changes through which it has been brought into its present condition, will appear neither to have been too slowly effected, nor to have been too complicated.

[21] “Geolog. Transact.,” vol. v, p. 626.

NOTE.—As, both in France and England, translations of a passage in Professor Ehrenberg’s Memoir, often referred to in the Fourth Chapter of this volume, have appeared, implying that Professor Ehrenberg believes, from the character of the infusoria, that the Pampean formation was deposited by a sea-debacle rushing over the land, I may state, on the authority of a letter to me, that these translations are incorrect. The following is the passage in question:—“Durch Beachtung der mikroscopischen Formen hat sich nun feststellen lassen, das die Mastodonten-Lager am La Plata und die Knochen-Lager am Monte Hermoso, who wie die der Riesen-Gürtelthiere in den Dünenhügeln bei Bahia Blanca, beides in Patagonien, unveränderte brakische Süsswasserbildungen sind, die einst wohl sämmtlich zum obersten Fluthgebiethe des Meeres im tieferen Festlande gehörten.”—_Monatsberichten der königl. Akad., etc.,_ zu Berlin vom April 1845.

INDEX TO CORAL-REEFS.

The names in italics are all names of places, and refer exclusively to the Appendix: in well-defined archipelagoes, or groups of islands, the name of each separate island is not given.

Abrolhos, Brazil, coated by corals 50 _Abrolhos (Australia)_ 130 Absence of coral-reefs from certain coasts 51 _Acaba, gulf of_ 147 _Admiralty group_ 124 Africa, east coast, fringing-reef of 48 —— Madreporitic rock of 101 _Africa, east coast_ 141 Age of individual corals 57, 64 _Aiou_ 128 _Aitutaki_ 114 _Aldabra_ 139 _Alert reef_ 123 _Alexander, Grand Duke, island_ 115 Allan, Dr., on Holuthuriæ feeding on corals 21 —— on quick growth of corals at Madagascar 62 —— on reefs affected by currents 9 _Alloufatou_ 119 _Alphonse_ 139 _Amargoura (Amargura)_ 119 _Amboina_ 128 _America, west coast_ 111 _Amirantes_ 138 _Anachorites_ 125 _Anambas_ 133 Anamouka, description of 99 _Anamouka_ 119 _Anadaman islands_ 132 _Antilles_ 153 _Appoo reef_ 134 _Arabia Felix_ 143 Areas, great extent of, interspersed with low islands —— of subsidence and of elevation 106 —— of subsidence appear to be elongated 106 —— of subsidence alternating with areas of elevation 108 _Arru group_ 128 _Arzobispo_ 127 Ascidia, depth at which found 67 _Assomption_ 139 _Astova_ 139 _Atlantic islands_ 121 Atolls, breaches in their reefs 31, 81 —— dimensions of 25 —— dimensions of groups of 71 —— not based on craters or on banks of sediment, or of ck 69, 71, 72, 73, 108 —— of irregular forms 25, 84 —— steepness of their flanks 26 —— width of their reef and islets 25 —— their lowness 70 —— lagoons 29 —— general range 94 —— with part of their reef submerged, and theory of 29, 81 _Augustine, St._ 120 Aurora island, an upraised atoll 64, 71, 104 _Aurora_ 112 Austral islands, recently elevated 99 _Austral islands_ 114 _Australia, N.W. coast_ 130 Australian barrier-reef 42, 93 _Australian barrier_ 123

_Babuyan group_ 134 _Bahama banks_ 149, 150 _Balahac_ 133 _Bally_ 131 _Baring_ 121 Barrier-reef of Australia 42, 93 —— of New Caledonia 44 Barrier-reefs, breaches through 77 —— not based on worn down margin of rock 43 —— on banks of sediment 43 —— on submarine craters 44 —— steepness of their flanks 39 —— their probable vertical thickness 43, 76 —— theory of their formation 76, 78 _Bampton shoal_ 123 _Banks islands_ 122 _Banks in the West Indies_ 147 _Bashee islands_ 134 _Bass island_ 115 _Batoa_ 119 _Beaupré reef_ 123 Beechey, Captain, obligations of the author to 26 —— on submerged reefs 27 —— account of Matilda island 60 Belcher, Captain, on boring through coral-reef 59 _Belize reef, off_ 151 _Bellinghausen_ 113 _Bermuda islands_ 153 _Beveridge reef_ 118 _Bligh_ 122 Bolabola, view of 12 _Bombay shoal_ 136 _Bonin Bay_ 131 _Bonin group_ 127 Borings through coral-reefs 59 Borneo, W. coast, recently elevated 101 _Borneo, E. coast_ 131 —— _S.W. and W. coast_ 133 —— _N. coast_ 133 —— _western bank_ 136 _Boscawen_ 119 _Boston_ 121 _Bouka_ 124 _Bourbon_ 138 _Bourou_ 128 _Bouton_ 132 Brazil, fringing-reefs on coast of 48 Breaches through barrier-reefs 71 _Brook_ 115 _Bunker_ 115 _Bunoa_ 133 Byron 121

_Cagayanes_ 133 _Candelaria_ 124 _Cargados Carajos_ 138 _Caroline archipelago_ 125 _Caroline island_ 115 _Carteret shoal_ 128 Caryophyllia, depth at which it lives 66 _Cavilli_ 133 _Cayman island_ 152 _Celebes_ 129 _Ceram_ 128 Ceylon, recently elevated 101 _Ceylon_ 137 Chagos Great Bank, description and theory of 37, 85 Chagos group 86 _Chagos group_ 137 Chama-shells embedded in coral-rock 68 Chamisso, on corals preferring the surf 52 Changes in the state of Keeling atoll 21 —— of atolls 74 Channels leading into the lagoons of atolls 30, 82 —— —— into the Maldiva atolls 33, 35 —— through barrier-reefs 77 _Chase_ 120 _China sea_ 135 Christmas atoll 60, 97 _Christmas atoll_ 116 _Christmas island_ (Indian Ocean) 137 _Clarence_ 116 _Clipperton rock_ 111 Cocos, or Keeling atoll 15 _Cocos (or Keeling)_ 137 _Cocos island_ (Pacific) 111 Cochin China, encroachments of the sea on the coast 95 _Cochin China_ 183 _Coetivi_ 139 _Comoro group_ 139 Composition of coral-formations 88 Conglomerate coral-rock on Keeling atoll 20 —— on other atolls 28 —— coral-rock 88 Cook islands, recently elevated 98, 103 _Cook islands_ 114 Coral-blocks bored by vermiform animals 21, 88 Coral-reefs, their distribution and absence from certain areas 50 —— destroyed by loose sediment 53 Coral-rock at Keeling atoll 20 —— Mauritius 47 —— organic remains of 88 Corals dead but upright in Keeling lagoon 22 —— depths at which they live 64 —— off Keeling atoll 17 —— killed by a short exposure 16 —— living in the lagoon of Keeling atoll 20 —— quick growth of, in Keeling lagoon 21 —— merely coating the bottom of the sea 50 —— standing exposed in the Low archipelago 96 Corallian sea 94 _Corallian sea_ 123 _Cornwallis_ 121 _Cosmoledo_ 139 Couthouy, Mr., alleged proofs of recent elevation of the Low archipelago 96 —— on coral-rock at Mangaia and Aurora islands 64 —— on external ledges round coral-islands 80 —— remarks confirmatory of the author’s theory 96 Crescent-formed reefs 84 _Cuba_ 150 Cuming, Mr., on the recent elevation of the Philippines 101

_Dangerous, or Low archipelago_ 111 _Danger islands_ 116 Depths at which reef-building corals live 63 —— at Mauritius, the Red Sea, and in the Maldiva archipelago 66 —— at which other corals and corallines can live 67 _Dhalac group_ 144 Diego Garcia, slow growth of reef 56 Dimensions of the larger groups of atolls 71 Disseverment of the Maldiva atolls, and theory of 37, 82 Distribution of coral-reefs 50 _Domingo, St._ 152 Dory, Port, recently elevated 100 _Dory, Port_ 127 _Duff islands_ 122 _Durour_ 125

_Eap_ 126 arthquakes at Keeling atoll 23 —— in groups of atolls 75 —— in Navigator archipelago 100 ast Indian archipelago, recently elevated 100 _Easter_ 111 _Echequier_ 125 hrenberg, on the banks of the Red Sea 49, 143 —— on depths at which corals live in the Red Sea 66 —— on corals preferring the surf 53 —— on the antiquity of certain corals 57 _Eimeo_ 112 levated reef of Mauritius 47 levations, recent proofs of 98 —— immense areas of 106 _Elivi_ 126 lizabeth island 59 —— recently elevated 98, 104 _Elizabeth island_ 112 _Ellice group_ 120 ncircled islands, their height 41 —— geological composition 42, 44 ua, description of 99 _Eoua_ 118 upted matter probably not associated with thick masses of coral-rock 89

Fais, recently elevated 100, 104 _Fais_ 126 _Fanning_ 116 _Farallon de Medinilla_ 127 _Farson group_ 144 _Fataka_ 122 Fiji archipelago 119 Fish, feeding on corals 21 —— killed in Keeling lagoon by heavy rain 24 Fissures across coral-islands 75 Fitzroy, Captain, on a submerged shed at Keeling atoll 23 —— on an inundation in the Low archipelago 74 _Flint_ 115 _Flores_ 130 _Florida_ 149 _Folger_ 127 _Formosa_ 135 Forster, theory of coral-formations 73 _Frederick reef_ 123 _Freewill_ 128 Friendly group recently elevated 99, 105 _Friendly archipelago_ 118 Fringing-reefs, absent where coast precipitous 5 —— breached in front of streams 54 —— described by MM. Quoy and Gaimard 98 —— not closely attached to shelving coasts 46 —— of east coast of Africa —— of Cuba 48 —— of Mauritius 45 —— on worn down banks of rock 9 —— on banks of sediment 49 —— their appearance when elevated 7 —— their growth influenced by currents 49 —— by shallowness of sea 49

_Galapagos archipelago_ 111 _Galega_ 139 Gambier islands, section of 43 _Gambier islands_ 112 _Gardner_ 116 _Gaspar rico_ 121 Geological composition of coral-formations

_Gilbert archipelago_ 120 _Gilolo_ 129 _Glorioso_ 139 Gloucester island 74 _Glover reef_ 152 _Gomez_ 111 _Gouap_ 126 _Goulou_ 126 _Grampus_ 127 _Gran Cocal_ 120 Great Chagos Bank, description and theory of 37, 85 Grey, Captain, on sandbars 46 Grouping of the different classes of reefs 93 _Guedes_ 128

Hall, Captain B., on Loo Choo 101 Harvey islands, recently elevated 104 Height of encircled islands 41 _Hermites_ 125 _Hervey or Cook islands_ 114 _Hogoleu_ 125 Holothuriæ (Holuthuriæ) feeding on coral 21 Houden island, height of 71 _Honduras, reef off_ 151 _Horn_ 119 _Houtman Abrolhos_ 130 Huaheine; alleged proofs of its recent elevation 103 _Huaheine_ 113 _Humphrey_ 115 _Hunter_ 119 Hurricanes, effects of, on coral-islands 74

_Immaum_ 143 _Independence_ 120 India, west coast, recently elevated 101 _India_ 143 Irregular reefs in shallow seas 49 Islets of coral-rock, their formation 19 —— their destruction in the Maldiva atolls 36

_Jamaica_ 152 _Jarvis_ 115 Java, recently elevated 100 _Java_ 131 _Johnston island_ 116 _Juan de Nova_ 139 _Juan de Nova (Madagascar)_ 140

_Kalatoa_ 131 Kamtschatka, proofs of its recent elevation 105 _Karkalang_ 129 Keeling atoll, section of reef 15 _Keeling, south atoll_ 137 —— _north atoll_ 137 _Keffing_ 128 _Kemin_ 115, 116 _Kennedy_ 123 _Keppel_ 119 _Kumi_ 135

_Laccadive group_ 137 Ladrones, or Marianas, recently elevated 100 _Ladrones archipelago_ 127 Lagoon of Keeling atoll 20 Lagoons bordered by inclined ledges and walls, and theory of their formation 32, 79 —— of small atolls filled up with sediment 32 Lagoon-channels within barrier-reefs 40 Lagoon-reefs, all submerged in some atolls, and rising to the surface in others 55 _Lancaster reef_ 115 _Latte_ 119 _Lauglan islands_ 123 Ledges round certain lagoons 32, 79 _Lette_ 129 _Lighthouse reef_ 152 Lloyd, Mr., on corals refixing themselves 62 Loo Choo, recently elevated 101 _Loo Choo_ 135 _Louisiade_ 123 Low archipelago, alleged proofs of its recent elevation 96 _Low archipelago_ 111 Lowness of coral-islands 70 _Loyalty group_ 123 _Lucepara_ 133 Lutké, Admiral, on fissures across coral-islands 75 Luzon, recently elevated 101 _Luzon_ 134 Lyell, Mr., on channels into the lagoons of atolls 31 —— on the lowness of their leeward sides 82 —— on the antiquity of certain corals 58 —— on the apparent continuity of distinct coral-islands 89 —— on the recently elevated beds of the Red Sea 102 —— on the outline of the areas of subsidence 106

_Macassar strait_ 131 _Macclesfield bank_ 136 Madagascar, quick growth of corals at 62 —— madreporitic rock of 101 _Madagascar_ 140 _Madjiko-sima_ 135 _Madura (Java)_ 131 _Madura (India)_ 137 Mahlos Mahdoo, theory of formation 88 Malacca, recently elevated 100 _Malacca_ 133 Malcolmson, Dr., on recent elevation of W. coast of India 100 —— on recent elevation of Camaran island 102 _Malden_ 115 Maldiva atolls, and theory of their formation 33, 80, 82 —— steepness of their flanks 26 —— growth of coral at 62 _Maldiva archipelago_ 137 Mangaia island 64 —— recently elevated 99, 104 _Mangaia_ 114 _Mangs_ 127 Marianas, recently elevated 100 _Mariana archipelago_ 127 _Mariere_ 126 _Marquesas archipelago_ 113 _Marshall archipelago_ 121 _Marshall island_ 127 _Martinique_ 153 _Martires_ 126 Mary’s St. in Madagascar, harbour made in reefs 54 _Mary island_ 116 _Matia, or Aurora_ 112 Matilda atoll 60 Mauritius, fringing-reefs of 45 —— depths at which corals live there 64 —— recently elevated 101 _Mauritius_ 138 Maurua, section of 43 _Maurua_ 113 Menchikoff atoll 25,

_Mendana archipelago_ 113 _Mendana isles_ 122 _Mexico, gulf of_ 149 Millepora complanata at Keeling atoll 16 _Mindoro_ 134 _Mohilla (Mohila)_ 139 Molucca islands, recently elevated 100 _Mopeha_ 113 Moresby, Captain, on boring through coral-reefs 59 _Morty_ 129 _Mosquito coast_ 152 Musquillo atoll 84 _Mysol_ 129

Namourrek group 84 _Natunas_ 133 Navigator archipelago, elevation of 99 _Navigator archipelago_ 117 _Nederlandisch_ 120 Nelson, Lieutenant, on the consolidation of coral-rocks under water 59 —— theory of coral-formations 73 —— on the Bermuda islands 154 _New Britain_ 124 New Caledonia, steepness of its reefs 39 —— —— barrier-reef of , 79, 83, 93 _New Caledonia_ 123 _New Guinea (E. end)_ 124 _New Guinea (W. end)_ 127 _New Hanover_ 124 New Hebrides, recently elevated 100 _New Hebrides_ 121 New Ireland, recently elevated 100 _New Ireland_ 124 _New Nantucket_ 116 _Nicobar islands_ 132 _Niouha_ 119 Nulliporæ at Keeling atoll 18 —— on the reefs of atolls 28 —— on barrier-reefs 39 —— their wide distribution and abundance 68

Objections to the theory of subsidence 7 _Ocean islands_ 117, 121 _Ono_ 120 _Onouafu (Onouafou)_ 119 _Ormuz_ 143 _Oscar group_ 120 Oscillations of level 103, 108 _Ouallan, or Ualan (Oualan)_ 125 Ouluthy atoll 60 _Outong Java_ 124

_Palawan, S.W. coast 133 —— N.W. coast 134 —— western bank 136 _ Palmerston 114 _Palmyra_ 116 _Paracells_ 136 _Paraquas_ 136 _Patchow_ 135 _Pelew islands_ 126 Pemba island, singular form of 102 _Pemba_ 142 _Penrhyn_ 115 _Peregrino_ 115 Pernambuco, bar of sandstone at 47 Persian gulf, recently elevated 102 _Persian gulf_ 143 Pescado 115 _Pescadores_ 135 _Peyster group_ 120 _Philip_ 126 Philippine archipelago, recently elevated 101 _Philippine archipelago_ 134 _Phœnix_ 116 _Piguiram_ 126 _Pitcairn_ 112 Pitt’s bank 86 _Pitt island_ 120 _Platte_ 139 _Pleasant_ 121 Porites, chief coral on margin of Keeling atoll 16 _Postillions_ 131 Pouynipète 95 —— its probable subsidence 95 _Pouynipète_ 125 _Pratas shoal_ 135 _Proby_ 119 _Providence_ 139 _Puerto Rico_ 152 _Pulo Anna_ 126 Pumice floated to coral-islands 88 _Pylstaart_ 118 Pyrard de Laval, astonishment at the atolls in the Indian Ocean 11

Quoy and Gaimard, depths at which corals live 66 —— description of reefs applicable only to fringing-reefs 98

Range of atolls 94 _Rapa_ 115 _Rearson_ 115 Red Sea, banks of rock coated by reefs 49 —— proofs of its recent elevation 102 —— supposed subsidence of 103 _Red Sea_ 143 Reefs, irregular in shallow seas 49 —— rising to the surface in some lagoons and all submerged in others 55 —— their distribution 50 —— their absence from some coasts 51 _Revilla-gigedo_ 111 Ring-formed reefs of the Maldiva atolls, and theory of , 80 _Rodriguez_ 138 _Rosario_ 127 _Rose island_ 118 _Rotches_ 120 _Rotoumah_ 120 _Roug_ 125 _Rowley shoals_ 130 Rüppell, Dr., on the recent deposits of Red Sea 102

_Sable, ile de_ 138 _Sahia de Malha_ 137 _St. Pierre_ 139 _Sala_ 111 _Salomon (Solomon) archipelago_ 123 Samoa, or Navigator archipelago, elevation of 99 _Samoa archipelago_ 117 Sand-bars parallel to coasts 46 _Sandal-wood_ 129 Sandwich archipelago, recently elevated 98 _Sandwich archipelago_ 117 _Sanserot_ 126 _Santa-Cruz group_ 122 Savage island, recently elevated 59, 99, 104 _Savage_ 118 _Savu_ 129 _Saya, or Sahia de Malha_ 137 _Scarborough shoal_ 136 Scarus feeding on corals 21 _Schouten_ 124 _Scilly_ 113 Scoriæ floated to coral-islands 89 _Scott’s reef_ 130 Sections of islands encircled by barrier-reefs 43, 176 —— of Bolabola 76 Sediment in Keeling lagoon 21 —— in other atolls 29, 35 —— injurious to corals 53 —— transported from coral-islands far seaward 89 _Seniavine_ 125 _Serangani_ 129 _Seychelles_ 138 Ship-bottom quickly coated with coral 62 _Smyth island_ 116 Society archipelago, stationary condition of 96 —— alleged proofs of recent elevation 103 _Society archipelago_ 112 _Socotra_ 143 _Solor_ 130 Sooloo islands, recently elevated 101 _Sooloo islands_ 133 _Souvaroff_ 115 _Spanish_ 126 Sponge, depths at which found 67 _Starbuck (Slarbuck)_ 115 Stones transported in roots of trees 89 Storms, effects of, on coral-islands 74 Stutchbury, Mr., on the growth of an Agaricia 63 —— on upraised corals in Society archipelago 103 Subsidence of Keeling atoll 28 —— extreme slowness of 87, 108 —— areas of, apparently elongated 106 —— areas of immense 106 —— great amount of 108 _Suez, gulf of_ 147 _Sulphur islands_ 127 Sumatra, recently elevated 100 _Sumatra_ 132 _Sumbawa_ 130 Surf favourable to the growth of massive corals 52 _Swallow shoal_ 136 _Sydney island_ 116

Tahiti, alleged proofs of its recent elevation 103 _Tahiti_ 112 Temperature of the sea at the Galapagos archipelago 51 _Tenasserim_ 133 _Tenimber island_ 128 _Teturoa_ 113 Theories on coral-formations 69, 73 Theory of subsidence, and objections to 72, 86 Thickness, vertical, of barrier-reefs 43, 76 _Thomas, St._ 153 _Tikopia_ 122 Timor, recently elevated 100 _Timor_ 129 _Timor-laut_ 128 _Tokan-Bessees_ 131 _Tongatabou_ 118 _Tonquin_ 137 _Toubai_ 113 _Toufoa (Toofoa)_ 119 _Toupoua_ 122 Traditions of change in coral-islands 73 Tridacnæ embedded in coral-rock 63 —— left exposed in the Low archipelago 96 Tubularia, quick growth of 63 _Tumbelan_ 133 _Turneffe reef_ 152 _Turtle_ 119

_Ualan_ 125

Vanikoro, section of 43 —— its state and changes in its reefs 95 _Vanikoro_ 122 _Vine reef_ 125 _Virgin Gorda_ 153 _Viti archipelago_ 119 Volcanic islands, with living corals on their shores 51 —— matter, probably not associated with thick masses of coral-rock 88 Volcanoes, authorities for their position on the map 90 —— their presence determined by the movements in progress 104 —— absent or extinct in the areas of subsidence 105

_Waigiou_ 128 _Wallis island_ 119 _Washington_ 116 _Wells’ reef_ 123 Wellstead, Lieutenant, account of a ship coated with corals 62 West Indies, banks of sediment fringed by reefs 49 —— recently elevated 102 _West Indies_ 147 Whitsunday island, view of 12 —— changes in its state 74 Williams, Rev. J., on traditions of the natives regarding coral-islands 74 —— on antiquity of certain corals 64 _Wolchonsky_ 111 _Wostock_ 115

_Xulla islands_ 128

_York island_ 116 _Yucutan, coast of_ 151

Zones of different kinds of corals outside the same reefs 55, 60

INDEX TO VOLCANIC ISLANDS.

Abel, M., on calcareous casts at the Cape of Good Hope 261 Abingdon island 234 Abrolhos islands, incrustation on 188 Aeriform explosions at Ascension 191 _Albatross_, driven from St. Helena 225 Albemarle island 234 Albite, at the Galapagos archipelago 234 Amygdaloidal cells, half filled 184 Amygdaloids, calcareous origin of 176 Ascension, arborescent incrustation on rocks of 188 —— absence of dikes, freedom from volcanic action, and state of lava-streams 226 Ascidia, extinction of 258 Atlantic Ocean, new volcanic focus in 226 Augite, fused 239 Australia 251 Azores 182, 248

Bahia in Brazil, dikes at 247 Bailly, M., on the mountains of Mauritius 185 Bald Head 260 Banks’ Cove 234, 236 Barn, The, St. Helena 216 Basalt, specific gravity of 245 Basaltic coast-mountains at Mauritiu 185 —— at St. Helena 218 —— at St. Jago 178 Beaumont, M. Elie de, on circular subsidences in lava 233 —— on dikes indicating elevation 228 —— on inclination of lava-streams 227 —— on laminated dikes 212 Bermuda, calcareous rocks of 260, 262 Beudant, M., on bombs 191 —— on jasper 197 —— on laminated trachyte 211 —— on obsidian of Hungary 207 —— on silex in trachyte 270, 197 Bole 257 Bombs, volcanic 189 Bory St. Vincent, on bombs 190 Boulders, absence in Australia and Cape of Good Hope 265 Brattle island 238 Brewster, Sir D., on a calcareo-animal substance 201 —— on decomposed glass 252 Brown, Mr. R., on extinct plants from Van Diemen’s land 257 —— on sphærulitic bodies in silicified wood 207 Buch, Von, on cavernous lava 233 —— on central volcanoes 249 —— on crystals sinking in obsidian 243 —— on laminated lava 209 —— on obsidian streams 208 —— on olivine in basalt 234 —— on superficial calcareous beds in the Canary islands 224

Calcareous deposit at St. Jago affected by heat 169, 171 —— fibrous matter, entangled in streaks in scoriæ 174 —— freestone at Ascension 198 —— incrustations at Ascension 199 —— sandstone at St. Helena 222 —— superficial beds at King George’s sound 260 Cape of Good Hope 263 Carbonic acid, expulsion of, by heat 171, 176 Carmichael, Capt., on glassy coatings to dikes 216 Casts, calcareous, of branches 261 Chalcedonic nodules 257 Chalcedony in basalt and in silicified wood 196 Chatham island 231, 235, 241, 248, 259 Chlorophæite 257 Clarke, Rev. W., on the Cape of Good Hope 258, 263 Clay-slate, its decomposition and junction with granite at the Cape of Good Hope 264 Cleavage of clay-slate in Australia 252 Cleavage, cross, in sandstone 253 Coast denudation at St. Helena 226 Columnar basalt 173 “Comptes Rendus,” account of volcanic phenomena in the Atlantic 226 Concepcion, earthquake of 228, 249 Concretions in aqueous and igneous rocks compared 206 —— in tuff 197 —— of obsidian 206, 208 Conglomerate, recent, at St. Jago 181 Coquimbo, curious rock of 261 Corals, fossil, from Van Diemen’s Land 256 Crater, segment of, at the Galapagos 238 —— great central one at St. Helena 219 —— internal ledges round, and parapet on 220 Craters, basaltic, at Ascension 189 —— form of, affected by the trade wind 189 —— of elevation 227 —— of tuff at Terceira 182 —— of tuff at the Galapagos archipelago 230, 231, 235, 237 —— their breached state 240 —— small basaltic at St. Jago 177 —— —— at the Galapagos archipelago 232 Crystallisation favoured by space 211

Dartigues, M., on sphærulites 207 Daubeny, Dr., on a basin-formed island 237 —— on fragments in trachyte 193 D’Aubuisson on hills of phonolite 222 —— on the composition of obsidian 206 —— on the lamination of clay-slate 210 De la Beche, Sir H., on magnesia in erupted lime 174 —— on specific gravity of limestones 198 Denudation of coast at St. Helena 226 Diana’s Peak, St. Helena 220 Dieffenbach, Dr., on the Chatham Islands 259 Dikes, truncated, on central crateriform ridge of St. Helena 219 —— at St. Helena; number of; coated by a glossy layer; uniform thickness of 216 —— great parallel ones at St. Helena 222 —— not observed at Ascension 226 —— of tuff 231 —— of trap in the plutonic series 247 —— remnants of, extending far into the sea round St. Helena 226 Dislocations at Ascension 192 —— at St. Helena 217, 221 Distribution of volcanic islands 248 Dolomieu, on decomposed trachyte 182 —— on laminated lava 210, 211 —— on obsidian 208 Drée, M., on crystals sinking in lava 243 Dufrenoy, M., on the composition of the surface of certain lava-streams 209, 243 —— on the inclination of tuff-strata 236

Eggs of birds embedded at St. Helena 224 —— of turtle at Ascension 198 Ejected fragments at Ascension 192 —— at the Galapagos archipelago 239 Elevation of St. Helena 225 —— the Galapagos archipelago 241 —— Van Diemen’s Land, Cape of Good Hope, New Zealand, Australia, and Chatham island 258 —— of volcanic islands 250 Ellis, Rev. W., on ledges within the great crater at Hawaii 220 —— on marine remains at Otaheite 184 Eruption, fissures of 224, 249, 250 Extinction of land-shells at St. Helena 224

Faraday, Mr., on the expulsion of carbonic acid gas 171 Feldspar, fusibility of 246 —— in radiating crystals 263 —— Labrador, ejected 193 Feldspathic lavas 179 —— at St. Helena 219 —— rock, alternating with obsidian 202 —— lamination, and origin of 209 Fernando Noronha 181, 210 Ferruginous superficial beds 259 Fibrous calcareous matter at St. Jago 174 Fissures of eruption 242, 249, 250 Fitton, Dr., on calcareous breccia 262 Flagstaff Hill, St. Helena 216 Fleurian de Bellevue on sphærulites 207 Fluidity of lavas 234, 235 Forbes, Professor, on the structure of glaciers 212 Fragments ejected at Ascension 192 —— at the Galapagos archipelago 239 Freshwater Bay 238, 243 Fuerteventura (Feurteventura), calcareous beds of 224

Galapagos archipelago 229 —— parapets round craters 220 Gay Lussac, on the expulsion of carbonic acid gas 171 Glaciers, their structure 212 Glossiness of texture, origin of 206 Gneiss, derived from clay-slate 264 —— with a great embedded fragment 252 Gneiss-granite, form of hills of 259 Good Hope, Cape of 263 Gorges, narrow, at St. Helena 225 Granite, junction with clay-slate, at the Cape of Good Hope 263 Granitic ejected fragments 192, 239 Gravity, specific, of lavas 243-8 Gypsum, at Ascension 201 —— in volcanic strata at St. Helena 215 —— on surface of the ground at ditto 223

Hall, Sir J., on the expulsion of carbonic acid gas 171 Heat, action of, on calcareous matter 170 Hennah, Mr., on ashes at Ascension 189 Henslow, Prof., on chalcedony 197 Hoffmann, on decomposed trachyte 182 Holland, Dr., on Iceland 228 Horner, Mr., on a calcareo-animal substance 201 —— on fusibility of feldspar 246 Hubbard, Dr., on dikes 247 Humboldt on ejected fragments 193 —— on obsidian formations 207, 209 —— on parapets round craters 220 —— on sphærulites 210 Hutton on amygdaloids 176 Hyalite in decomposed trachyte 182

Iceland, stratification of the circumferential hills 228 Islands, volcanic, distribution of 248 —— their elevation 250 Incrustation, on St. Paul’s rocks 187 Incrustations, calcareous, at Ascension 199

Jago, St. 167 James island 234, 237, 242 Jasper, origin of 196 Jonnès, M. Moreau de, on craters affected by wind 189 Juan Fernandez 250

Keilhau, M., on granite 264 Kicker Rock 232 King George’s sound 259

Labrador feldspar, ejected 193 Lakes at bases of volcanoes 229 Lamination of volcanic rocks 209 Land-shells, extinct, at St. Helena 224 Lanzarote, calcareous beds of 223 Lava, adhesion to sides of a gorge 177 —— feldspathic 179 —— with cells semi-amygdaloidal 184 Lavas, specific gravity of 243, 247 Lava-streams blending together at St. Jago 177 —— composition of surface of 208 —— differences in the state of their surfaces 244 —— extreme thinness of 238 —— heaved up into hillocks at the Galapagos archipelago 233 —— their fluidity 234, 235 —— with irregular hummocks at Ascension 189 Lead, separation from silver 244 Lesson, M., on craters at Ascension 189 Leucite 234 Lime, sulphate of, at Ascension 200 Lonsdale, Mr., on fossil-corals from Van Diemen’s land 256 Lot, St. Helena 221 Lyell, Mr., on craters of elevation 227 —— on embedded turtles’ eggs 198 —— on glossy coating to dikes 216

Macaulay, Dr., on calcareous casts at Madeira 262 MacCulloch, Dr., on an amygdaloid 184 —— on chlorophæite 287 —— on laminated pitchstone 209 Mackenzie, Sir G., on cavernous lava-streams 233 —— on glossy coatings to dikes 216 —— on obsidian streams 208 —— on stratification in Iceland 228 Madeira, calcareous casts at 262 _Magazine, Nautical,_—account of volcanic phenomena in the Atlantic 226 Marekanite 206 Mauritius, crater of elevation of 184, 227 Mica, in rounded nodules 168 —— origin in metamorphic slate 264 —— radiating form of 263 Miller, Prof., on ejected Labrador feldspar 193 —— on quartz crystals in obsidian beds 202 Mitchell, Sir T., on bombs 191 —— on the Australian valleys 254 Mud streams at the Galapagos archipelago 236

Narborough island 234 Nelson, Lieut., on the Bermuda islands 260, 262 New Caledonia 248 New Red sandstone, cross cleavage of 253 New South Wales 251 New Zealand 259 Nulliporæ (fossil), resembling concretions 169

Obsidian, absent at the Galapagos archipelago 241 —— bombs of 191 —— composition and origin of 207, 208 —— crystals of feldspar sink in 243 —— its irruption from lofty craters 246 —— passage of beds into 202 —— specific gravity of 243, 246 —— streams of 208 Olivine decomposed at St. Jago 178 —— at Van Diemen’s land 257 —— in the lavas at the Galapagos archipelago 234 Oolitic structure of recent calcareous beds at St. Helena 223 Otaheite 183 Oysters, extinction of 258

Panza islands, laminated trachyte of 209 Pattinson, Mr., on the separation of lead and silver 244 Paul’s, St., rocks of 187 Pearlstone 206 Peperino 232 Péron, M., on calcareous rocks of Australia 262, 263 Phonolite, hills of 179, 181, 221 —— laminated 210 —— with more fusible hornblende 246 Pitchstone 204 —— dikes of 209 Plants, extinct 257 Plutonic rocks, separation of constituent parts of, by gravity 246 Porto Praya 167 Prevost, M. C., on rarity of great dislocations in volcanic islands 217 Prosperous hill, St. Helena 218 Pumice, absent at the Galapagos archipelago 241 —— laminated 209, 210, 211 Puy de Dome, trachyte of 193

Quail island, St. Jago 168, 170, 173 Quartz, crystals of, in beds alternating with obsidian 202 —— crystallised in sandstone 252 —— fusibility of 246 —— rock, mottled from metamorphic action with earthy matter 170

Red hill 173 Resin-like altered scoriæ 171 Rio de Janeiro, gneiss of 252 Robert, M., on strata of Iceland 228 Rogers, Professor, on curved lines of elevation 249

Salses, compared with tuff craters 240 Salt deposited by the sea 200 —— in volcanic strata 201, 215 —— lakes of, in craters 240 Sandstone of Brazil 265 —— of the Cape of Good Hope 265 —— platforms of, in New South Wales 252, 265 Schorl, radiating 263 Scrope, Mr. P., on laminated trachyte 209, 210, 212 —— on obsidian 208 —— on separation of trachyte and basalt 244 —— on silex in trachyte 176 —— on sphærulites 210 Seale, Mr., geognosy of St. Helena 215 —— on dikes 226 —— on embedded birds’ bones 225 Seale, on extinct shells of St. Helena 224 Sedgwick, Professor, on concretions 206 Septaria, in concretions in tuff 198 Serpulæ on upraised rocks 185 Seychelles 248 Shells, colour of, affected by light 201 —— from Van Diemen’s land 256 —— land, extinct, at St. Helena 224 —— particles of, drifted by the wind at St. Helena 223 Shelly matter deposited by the waves 200 Siau, M., on ripples 254 Signal Post Hill 168, 175, 176 Silica, deposited by steam 182 —— large proportion of, in obsidian 206, 208 —— specific gravity of 246 Siliceous sinter 196 Smith, Dr. A., on junction of granite and clay-slate 264 Spallanzani on decomposed trachyte 182 Specific gravity of recent calcareous rocks and of limestone 198 —— of lavas 245 Sphærulites in glass and in silicified wood 207 —— in obsidian 204, 210 Sowerby, Mr. G. B., on fossil-shells from Van Diemen’s land 256 —— from St. Jago 169 —— land-shells from St. Helena 224 St. Helena 214 —— crater of elevation of 227 St. Jago, crater of elevation of 227 —— effects of calcareous matter on lava 231 St. Paul’s rocks 187, 248 Stokes, Mr., collections of sphærulites and of obsidians 207, 212 Stony-top, Little 218, 222 —— Great 218 Stratification of sandstone in New South Wales 253, 255 Streams of obsidian 208 Stutchbury, Mr., on marine remains at Otaheite 184 Subsided space at Ascension 192

Tahiti 183 Talus, stratified, within tuff craters 236 Terceira 182 Tertiary deposit of St. Jago 169 Trachyte, absent at the Galapagos archipelago 241 —— at Ascension 193 —— at Terceira 182 —— decomposition of, by steam 182 —— its lamination 200, 210 —— its separation from basalt 244 —— softened at Ascension 194 —— specific gravity of 245 —— with singular veins 195 Trap-dikes in the plutonic series 247 —— at King George’s sound 259 Travertin at Van Diemen’s land 257 Tropic-bird, now rare, at St. Helena 225 Tuff, craters of 231, 235, 236 —— their breached state 240 —— peculiar kind of 231 Turner, Mr., on the separation of molten metals 244 Tyerman and Bennett on marine remains at Huaheine 184

Valleys, gorge-like, at St. Helena 225 —— in New South Wales 254 —— in St. Jago 180 Van Diemen’s land 256 Veins in trachyte 195 —— of jasper 195 Vincent, Bory St., on bombs 190 Volcanic bombs 189 —— island in process of formation in the Atlantic 226 —— islands, their distribution 248

Wacke, its passage into lava 183, 257 Wackes, argillaceous 168, 178 Webster, Dr., on a basin-formed island 237 —— on gypsum at Ascension 201 White, Martin, on soundings 254 Wind, effects of, on the form of craters

INDEX TO SOUTH AMERICAN GEOLOGY.

Abich, on a new variety of feldspar 446 Abrolhos islands 415 Absence of recent formations on the S. American coasts 409 Aguerros on elevation of Imperial 305 Albite, constituent mineral in andesite 446 —— in rocks of Tierra del Fuego 427 —— in porphyries 444 —— crystals of, with orthite 447 Alison, Mr., on elevation of Valparaiso 307, 310 Alumina, sulphate of 439 Ammonites from Concepcion 400, 405 Amolanas, Las 493 Amygdaloid, curious varieties of 444 Amygdaloids of the Uspallata range 471 —— of Copiapo 498 Andesite of Chile 446 —— in the valley of Maypu 449, 450 —— of the Cumbre pass 460, 466 —— of the Uspallata range 475 —— of Los Hornos 480 —— of Copiapo 488, 491 Anhydrite, concretions of 450, 463 Araucaria, silicified wood of 394, 474 Arica, elevation of 323 Arqueros, mines of 481 Ascension, gypsum deposited on 328 —— laminated volcanic rocks of 439, 440 Augite in fragments, in gneiss 414 —— with albite, in lava 347 Austin, Mr. R. A. C., on bent cleavage lamina 434 Austin, Captain, on sea-bottom 302 Australia, foliated rocks of 438 _Azara labiata_, beds of, at San Pedro 277, 352

_Baculites vagina_ 400 Bahia Blanca, elevation of 280 —— formations near 355 —— character of living shells of 408 Bahia (Brazil), elevation near 280 —— crystalline rocks of 414 Ballard, M., on the precipitation of sulphate of soda 349 Banda Oriental, tertiary formations of 365 —— crystalline rocks of 418 Barnacles above sea-level 311 —— adhering to upraised shells 306 Basalt of S. Cruz 389 —— streams of, in the Portillo range 456 —— in the Uspallata range 472 Basin chains of Chile 333 Beagle Channel 427, 430 Beaumont, Elie de, on inclination of lava-streams 390, 457 —— on viscid quartz-rocks 475 Beech-tree, leaves of fossil 391 Beechey, Captain, on sea-bottom 299 Belcher, Lieutenant, on elevated shells from Concepcion 306 Bella Vista, plain of 325 Benza, Dr., on decomposed granite 417 Bettington, Mr., on quadrupeds transported by rivers 374 Blake, Mr., on the decay of elevated shells near Iquique 322 —— on nitrate of soda 346 Bole 444 Bollaert, Mr., on mines of Iquique 503 Bones, silicified 402 —— fossil, fresh condition of 366 Bottom of sea off Patagonia 292, 298 Bougainville, on elevation of the Falkland islands 290 Boulder formation of S. Cruz 285, 295 —— of Falkland islands 290 —— anterior to certain extinct quadrupeds 371 —— of Tierra del Fuego 391 Boulders in the Cordillera 339, 341 —— transported by earthquake-waves 344 —— in fine-grained tertiary deposits 401 Brande, Mr., on a mineral spring 461 Bravais, M., on elevation of Scandinavia 320 Brazil, elevation of 279 —— crystalline rocks of 414, 418 Broderip, Mr., on elevated shells from Concepcion 306 Brown, Mr. R., on silicified wood of Uspallata range 474 Brown, on silicified wood 495 Bucalema, elevated shells near 307 Buch, Von, on cleavage 438 —— on cretaceous fossils of the Cordillera 453, 465 —— on the sulphureous volcanoes of Java 509 Buenos Ayres 352 Burchell, Mr., on elevated shells of Brazil 279 Byron, on elevated shells 303

Cachapual, boulders in valley of 339, 341 Caldcleugh, Mr., on elevation of Coquimbo 314 —— on rocks of the Portillo range 456 Callao, elevation near 323 —— old town of 327 Cape of Good Hope, metamorphic rocks of 439 _Carcharias megalodon_ 402 Carpenter, Dr., on microscopic organisms 352 Castro (Chiloe), beds near 394 Cauquenes Baths, boulders near 339, 341 —— pebbles in porphyry near 443 —— volcanic formation near 447 —— stratification near 449 Caves above sea-level 303, 307, 322 _Cervus pumilus,_ fossil-horns of 304 Chevalier, M., on elevation near Lima 323 Chile, structure of country between the Cordillera and the Pacific 333 —— tertiary formations of 337 —— crystalline rocks in 435 —— central, geology of 441 —— northern, geology of 479 Chiloe, gravel on coast 294 —— elevation of 303 —— tertiary formation of 337, 405 —— crystalline rocks of 433 Chlorite-schist, near M. Video 419 Chonos archipelago, tertiary formations of 393 —— crystalline rocks of 430 Chupat, Rio, scoriæ transported by 280 Claro, Rio, fossiliferous beds of 485 Clay-shale of Los Hornos 480 Clay-slate, formation of, Tierra del Fuego 424 —— of Concepcion 433 —— feldspathic, of Chile 442, 444, 448 —— —— of the Uspallata range 468, 470 —— black siliceous, band of, in porphyritic formations of Chile 445 Claystone porphyry, formation of, in Chile 442 —— origin of 445 —— eruptive sources of 444 Cleavage, definition of 414 —— at Bahia 415 —— Rio de Janeiro 415 —— Maldonado 418 —— Monte Video 420 —— S. Guitru-gueyu 421 —— Falkland I. 424 —— Tierra del Fuego 428 —— Chonos I. 434 —— Chiloe 435 —— Concepcion 434 —— Chile 435 —— discussion on 436 Cleavage-laminæ superficially bent 434 Cliffs, formation of 301 Climate, late changes in 345 —— of Chile during tertiary period 408 Coal of Concepcion 399 —— S. Lorenzo 504 Coast-denudation of St. Helena 301 Cobija, elevation of 322 Colombia, cretaceous formation of 504 Colonia del Sacramiento, elevation of 278 —— Pampean formation near 355 Colorado, Rio, gravel of 295 —— sand-dunes of 281, 294 —— Pampean formation near 355 Combarbala 479, 481 Concepcion, elevation of 305 —— deposits of 399, 405 —— crystalline rocks of 433 Conchalee, gravel-terraces of 311 Concretions of gypsum, at Iquique 345 —— in sandstone at S. Cruz 387 —— in tufaceous tuff of Chiloe 387 —— in gneiss 414 —— in claystone-porphyry at Port Desire 421 —— in gneiss at Valparaiso 435 —— in metamorphic rocks 436 —— of anhydrite 450 —— relations of, to veins 473 Conglomerate claystone of Chile 443, 445 —— of Tenuyan 454, 458, 478 —— of the Cumbre Pass 462, 466 —— of Rio Claro 485 —— of Copiapo 496, 499 Cook, Captain, on form of sea-bottom 300 Copiapo, elevation of 321 —— tertiary formations of 403 —— secondary formations of 489 Copper, sulphate of 489 —— native, at Arqueros 482 —— mines of, at Panuncillo 481 —— veins, distribution of 505 Coquimbo, elevation and terraces of 312 —— tertiary formations of 404 —— secondary formations of 482 Corallines living on pebbles 299 Cordillera, valleys bordered by gravel fringes 337 —— basal strata of 442 —— fossils of 453, 465, 486, 487, 493, 503 —— elevation of 442, 459, 474, 476, 500, 502, 510, 512, 517 —— gypseous formations of 450, 452, 461, 463, 479, 483, 489, 491, 503 —— claystone-porphyries of 442 —— andesitic rocks of 446 —— volcanoes of 447, 511, 517 Coste, M., on elevation of Lemus 303 Coy inlet, tertiary formation of 390 _Crassatella Lyellii_ 392 Cruickshanks, Mr., on elevation near Lima 327 Crystals of feldspar, gradual formation of, at Port Desire 422 Cumbre, Pass of, in Cordillera 502 Cuming, Mr., on habits of the Mesodesma 310 —— on range of living shells on west coast 407