Art. XXIII.—On the Volcanoes of the Pacific.
[Read before the Wellington Philosophical Society, 12th December, 1899.]
Third Line or Area of Elevation.
Having completed my second line of activity,* I will now follow the third line or area of elevation west to east along the 20th parallel of south latitude, which includes the greatest breadth, as it were, of the Pacific volcanic groups, from the coral sea bordering Australia to Easter Island; although here again it might be more correct for me to include the volcanic islands in the Malay Archipelago itself, and make the area one of elevation from Sumatra to a little to the eastward of Easter
[Footnote] * See Trans. N.Z. Inst., vol xxxi., Art. xlix.
Island in a general north-west and south-east direction, including as far north as the Philippines, and so as to embrace the greatest number of the Pacific islands. The actual trend of the islands will be found lying generally in a west-northwest and east-south-east direction, although many vary from those points.
Professor Milne places this area in his map as one of subsidence, wherein it will be seen how greatly we differ. The trinolith at Tongatabu happens to be a very good landmark as to sea-levels, and it shows that that island, at any rate, has not subsided 6 in. a century for the past three or four thousand years. Instances are within our own knowledge of the rapid growth of volcanic islands. “In 1796 a volume of smoke was seen to rise from the Pacific Ocean about thirty miles to the north of Unalaska. The ejected materials having raised the crater above the level of the water, the usual volcanic phenomena occurred. Repeated eruptions have increased the dimensions of the island until now it is several thousand feet in height and between two and three miles in circumference.” So that there is really no geological objection to the upheaval and formation of any of the groups of islands in the Pacific.
I am at once met with the objection that there is no line of present volcanic activity along the 20th parallel of south latitude. That is so; but nevertheless a glance at the map shows that there has been a line of upheaval, and my duty is to record in such a paper as this all the evidence I can collect bearing upon volcanic action in the Pacific, a region which hitherto has not met from vulcanologists that attention which it merits—the grandest volcanic region, I take it, upon the face of the globe. Great earth-oscillations doubtless occur in this immense water-area—seventy million square miles. There could not, of course, be so much volcanic activity without this vast water-area. The pressure of 30,920 ft. of sea-water near Tonga upon each foot of the ocean-bed at 62 ½lb. to the foot can be readily calculated. Such a column of water would readily find out any weak crack or crevice to reach the central heat or the imprisoned lava within the earth's crust. But, of course, the more surface-water that pours in the more quickly steam is generated, which by upheaval closes up the fault or crevice.
Thus, as I have already said, the bottom of the ocean is blistered by upheavals and volcanic growths—viz., the various groups of islands—and although we find no active volcanoes along this third line, yet I am not prepared to admit that volcanic action is quiescent, for one of the greatest tidal waves on record within the past twenty-five years arose from a submarine explosion in 21° 22′ S. latitude and 71° 5′ W. longitude—the 1877 wave described by Milne and others, which,
like the wave of 1868 and all the other great waves, travelled almost the length and breadth of the Pacific.
Accepting as a maxim the statement that an earthquake is an incomplete volcano, the islands along this line experience pretty sharp earth-movements; at present correct observations of them are not taken at all. Thus as I write news comes (dated 8th August, 1899) of a tidal wave which burst into Valparaiso Bay, damaging Government property to the extent of millions of dollars. Great parts of the embankment were carried away, and railway-cars and locomotives were dashed off the rails and embedded in the débris, the rails being torn and cranes smashed. Many thousand tons of merchandise were destroyed. The State railway between Bellavista and Baron was completely wrecked. This may only have been a local phenomenon, but a few of the islands in the Paumotus are sometimes washed clean by tidal waves.
The continuous pressure upon the ocean-bed at the deepest soundings between Tonga and New Zealand at 800 tons to the foot (34,848,000 tons to the acre, and 22,400,000,000 tons to the square mile) is so enormous that it is no wonder we find great volcanic activity within a certain radius from it. Where are we to look for the balance ? At our hotlake district in New Zealand, or at Tanna or Ambrym, in the New Hebrides ? Supposing we found thermal action going on regularly at eight- to ten-minute intervals in the geysers or fumaroles at our hot lakes, or similar discharges at Tanna or Ambrym in the New Hebrides, might we not conclude that these are the safety-valve escapes from the enormous pressure referred to, and that the regularity of the escaping steam proves a certain connection within the whole circle of which the points referred to are radii? The pulsations fairly average twelve minutes at the three points named, yet some sixteen hundred miles apart; so I think Sir James Hector ought to grant a greater area of unity in volcanic phenomena than he does.
It will be seen, too, that I differ very considerably from Milne's chart in my three lines or areas of activity and upheaval, as he gives them all as subsiding. It may be he is right with regard to those islands near to and north of the equator and with Easter Island and with some of the Paumotus; but the really subsiding area in the Pacific—viz., an ocean band of about a thousand miles in width following the south - east and north - west trend of the western coast of the American Continent—he does not give at all. But even this subsidence is so slight as to be almost unnoticeable, for we can even not be guided by the Easter Island images, whose gradual subsidence maybe only a local phenomenon, as I fancy much of the subsidence amounts to in the Pacific.
The one real and prominent fact in regard to the island groups in the Pacific is that they have been upheaved, since which a certain amount of subsidence has followed, but so slight that, as I have said, the Langiis at Tonga still remain much as they were built some three or four thousand years ago. There may be now a period of rest, but even that supposition I cannot agree with, so many slight changes do I know of taking place. I must say that Milne concludes his book in quite as uncertain a frame of mind as I am myself. The field is so vast and our knowledge so slight. The coral borings at Funafuti may tell us something, but even the sinking of a volcanic hill or blister near the equator some 1,500 ft. below the sea after upheaval, somewhat like Falcon Island, but to a greater depth, may only be a local phenomenon, telling us nothing of the general law of lines of activity or subsidence to which I am referring in this paper.
The opinion of leading geologists belonging to this Institute is that there are no “lines of activity,” each volcanic rent being local to itself. What, then, of the great line running north to south, bordering the Pacific, in the two American continents? And another line might be drawn fringing the Pacific on the other side—namely, through Japan and the Kurile Islands.
Beginning with the phenomena upon the islands where the first two lines of activity intersect each other—viz., the Loyalty Islands: Attention has already been called to the Rev. Mr. Turner's remarks “that Lifu is an uplifted coral formation, the highest land on the islands being about 300ft. above sea-level; and Mare a mass of uplifted coral, also bearing marks of two distinct upheavals.”
The peculiar formation of the islands lying off the mouth of Nei-afo Harbour in Vavau (Tonga) now require reference. The whole of them appear to be at an exact uniform level of 100 ft. to 200 ft. above the sea, evidently showing the same upheaval. They look just as if they were bits of reef upheaved. In no other way could they have acquired their flat tops and straight sides. “The power which exhausts itself in the eruption of a volcano often shows itself by the changes it produces in the level of the surrounding country.” I do not think that any land in the three great islands of Tonga is much more than 300 ft. above sea-level; Tongatabu much lower. The highest land I know is in Vavau: that island contains a great open grassy plain about 200 ft. high, unstocked, owing to the absence of water. The soil of Vavau and the surrounding islands is an excellent rich brown one, evidently volcanic. No doubt this soil came from the original volcanic rock, which has weathered, decomposed, and speedily clothed itself with vegetation.
It will be seen at a glance what an excellent soil the brown gravel in the little specimen-bottle upon the table from Falcon Island (now sunk below sea-level) would decompose into if allowed sufficient time; so that from this specimen it can be seen how much of the volcanic soil in the Pacific has been formed. I obtained the gravel before the island disappeared.
There is no water, as I have said, in Tonga except that which is caught in tanks, nor is rain very abundant there, but the night-dews are heavy. The natives bathe in the sea, and use very little water for cooking purposes; their chief drink being from the cocoanut. Their cooking is done by pouring about a pint of water into a huge earthen pot, closing the neck, and converting the water into steam. Clothes they do without, so that the thirty thousand people there rub along very well without much water. The Europeans, of course, use tanks, but the water these tanks contain must be a living mass of microbic germs.
Pylstaart, Kao, Letté, and Tofua are separate small islands to Tongatabu, Hapaai, and Vavau, and tower up, as I have said, from 700 ft. to 3,000 ft. They may have attained these heights by sudden growth, and yet not altered the levels of the three large islands.
Writing of Savage Island, Mr. Turner says, “It is an uplifted coral island 300 ft. above the level of the sea, about forty miles in circumference, in 19° S. latitude and 170° W. longitude.” It will be noticed that Savage Island, the Tongan Group, and the Loyalties, stretching some twelve hundred miles west to east, show an upheaval of 50 ft. to 300 ft. above sea-level.
The Cook or Hervey Group, over five hundred miles to the eastward, may also be embraced in this line, for with the exception of Rarotonga, which is volcanic and mountainous, the other islands consist of ancient coral formation raised 20 ft. to 200 ft. above the sea, some of them lower, and all surrounded by living coral reefs.
Mangaia, the southernmost island of the group, is of coral formation, but otherwise differs from most of the South Sea islands outside this group. It is about 650 ft. high, and at a distance appears quite flat. There is a fringing reef all round, about 2 cable lengths from the shore, and about 2 ft. above high-water mark, but with no passage for boats. Boats anchor outside the reef on a ledge, and canoes come off for passengers, &c. The natives then look out for the rise of the swell, land the canoes on the reef, jump out quickly, and drag the canoe to land before the receding sea can sweep it back into deep water. These facts go to prove a late upheaval at Mangaia.
Yet Rarotonga, a hundred miles west by north of Mangia,
is 2,920 ft. in height, seven miles long, and four miles wide, with the usual barrier reef. Of course, there is nothing to have prevented Rarotonga having been upheaved 200 ft. to 600 ft. at the same time as Mangaia was uplifted. So with Atiu or Vatiu Island in this group (latitude 19° 59′ S., longitude 158° 6′ W.), whose formation much resembles Mangaia, with a reef closely fringing the shore. Its highest point is 394 ft. above sea-level.
I cannot say whether the sides of these two islands are perpendicular or show two or more upheavals. My friend Mr. Moss, the late British Resident there, may be able to tell us, but I should think they would show either one or two upheavals, as nature generally acts slowly in such changes. The islands at the entrance to Vavau Harbour and the heads of that harbour itself are straight up and down—so much so that the men-of-war use them for target-practice. I should therefore suppose that this area of upheaval, when it occurred, rose about 200 ft. On the other hand, it may only have been tilted up by slow degrees, like the western foot-coast of the South American Andes, in the supposed crumpling or buckling of the earth's crust. But the islands present so up-heaved an appearance that one is led to that conclusion. A careful study of the rock-formation of each islet will settle the question. If the rock is old coral-formation upheaval cannot be questioned.
The 200 ft. to 300 ft. upheaval is also shown in the Austral Islands, lying further to the east and southward. These islands are high and fertile, Rurutu having a high central peak with lower eminences sloping to the shore. Around the foot of the mountains is a plain about a quarter of a mile wide, which consists of coral-formation, well covered with earth washed from the sides of the adjacent eminences, which has gradually constituted a soil teeming with luxuriant vegetation. Large coral masses rise here and there, abruptly in some instances, to the height of more than 200 ft. above the beach.
The Society Islands, rising 7,000 ft. above sea-level, show great ancient volcanic disturbance, but space will not allow me fully to describe them now. In Tahiti, the most important island of the group, volcanic substances, stratified, broken, and thrown up in the wildest disorder, are every where to be met with.
In the Paumotu, or Low, Archipelago there are many evidences of upheaval, and, of course, subsidence. The soil of Pitcairn Island, where the mutineers of the “Bounty” took refuge, is very rich but porous, a great portion being decomposed lava, the remainder a rich black earth. I should consider Henderson or Elizabeth Island (latitude 21° 21′ S., longitude 128° 19′ W.) within the range of the line of up-heval
I am now referring to. According to Captain Beechey the island is five miles long and one mile wide, and has a flat surface, nearly 80 ft. above the sea. All sides, excepting the north, is bounded by perpendicular cliffs, about 50 ft. high, composed entirely of dead coral, which are considerably undermined by the action of the waves. (This is exactly what one sees at Vavau, Tonga, and I recommend visitors not to miss pulling into one of these caves at the entrance to Vavau Harbour). Byron's Cave there, I expect, was similarly formed.
The external form of the Gambier Islands, in the Paumotus, conveys at once an impression of their volcanic origin, but the seventy-eight islands or groups of islands comprising the Paumotus are generally low islands almost a-wash. The hurricane of 1878, indeed, swept over some of them, carrying every living thing away. It is not often this group is visited by such cyclones. Many of the inhabitants saved themselves by tying themselves to the trunks of trees. It may be that the whole of the Paumotu Islands, under the 200 ft. level, appeared above the sea at the same upward movement to which I am at present referring. The uprising tapered off, as it were, at a little beyond Easter Island, and affected the whole equatorial area right through, perhaps to the western coast-line of the Australian Continent. It will be noticed that the 20th parallel of south latitude very nearly cuts all these islands.
The distance from the Loyalties to Henderson Island is about 3,580 miles, and the evidence which I have been able to produce shows one area of upheaval. It will be noticed, too, that this line is almost at right angles to the first line of present volcanic activity referred to in this paper, bounding the 180th parallel of longitude from Tarawera to Nei-afo, a distance of fifteen hundred miles, or in its fullest extent from Mounts Erebus and Terror to the equator, a distance of about four thousand five hundred miles; the second line of activity, from Hunter Island and through the New Hebrides, the Solomons, and New Britain, &c., to the longitude of Vulcan Island in New Guinea or Uap in the Carolines, being fully 2,250 miles; but this latter line would be better extended another two thousand miles of eastern longitude, so as to include the whole line of present activity through the Malay Archipelago.
Reference will be made directly to the islands immediately bordering on and north of the equator, which are all, with few exceptions, low and small. All these show subsidence. There are a great number of crescent- and low-shaped atolls in these northern, central, and eastern portions of the Pacific; also small, circular, sunken patches of coral, showing that during the
subsidence which accompanied and succeeded the upheavals the coral-polyp started its labours on the top of an extinct volcano or from a rugged ridge or peak. The evidences are common in the Pacific for a volcanic hill to subside, the crater to become a lake or a lagoon, the island to sink still further, and end in being an atoll or a crescent- or low-shaped reef, or finally a sunken coral-patch. At the same time, with these evidences of subsidence, there is this third area of upheaval. Nor can there be subsidence in the earth's crust without upheaval somewhere. But my task is only to record the facts I have seen or collected regarding these islands.
We must ask residents in the islands to keep a careful record of observation in land- and sea-levels. At present it may only be that the Pacific Ocean is deepening slightly in consequence of a slight shallowing of the Atlantic or Indian Oceans, which would account for the marvellous energy of the coral-polyp—an animal that must go on building as the waters deepen. Neither in the Atlantic nor Indian Oceans is there anything approaching the coral-growth we find in the Pacific. At Easter Island the carved tuff images are slowly descending into the sea. In the physical geography of the earth I am inclined to the belief that all change is slow and gradual, and not violent. At times, here and there, we experience a great volcanic eruption, but it is confined strictly to a very circumscribed locality.
Soundings amongst the islands are very steep—200 to 600 fathoms (1,200 ft. to 3,600 ft.), and this sometimes close up to the reefs. One can easily understand this, however, looking at the rugged volcanic shape of the islands of Fiji, Samoa, or Tahiti. And the deepest soundings on earth, as already pointed out, lie between New Zealand and Tonga—5,155 fathoms (30,930 ft.), latitude 30° 27′ S. and longitude 176° 39′ W.; so that the oceans would have to overflow the tops of the Himalayas a couple of thousand feet before the supposed sunken Pacific continent could be again exposed.
Let us suppose a piece of land a hundred miles square, like the narrow neck between Auckland and Onehunga, containing a similar number of extinct craters sunk beneath the sea in the tropics. The coral-polyp would begin its labours directly from the top of the different extinct craters, go on building upwards to the sea-surface, and we should have all the evidences of atolls and circular-shaped reefs, but not, of course, on so large a scale as we find in the Pacific.
In the Sandwich Islands the United States steamer “Tuscarora,” at a distance of only forty-three miles from Molokai, found 3,023 fathoms, or over 18,138 ft. Add this to the height of Maunakea, the highest point in Hawaii (13,805 ft.), and we have 31,943 ft., or 3,773 ft. higher than the loftiest peak of
the Himalayas, which is only 28,170 ft. Am I therefore justified in slightly doubting this “sunken continent” theory, and in thinking that our equatorial belt and polar depressions must have been fairly fixed in their present positions at the original cooling of the planet, and, from the volcanic phenomena in the Pacific, that our views of geological science must be modified.
I would point out the great lengths and breadths of the volcanic lines I have been speaking of. The islands forming the Wallis Group show the 200 ft. upward or outward thrust equally with the Tongan islands. These small islands do not show any lines of fracture on the land, but rather a distinct outward thrust. It appears as if the earth's crust uprose in this special geographical area in prehistoric times some 200 ft. to 250 ft. in one gentle movement, since which time the islands have remained about stationary, the ocean waves, however, washing them slowly away. Their flat tops or sharp peaks to me show every evidence of their former submergence. Nevertheless, each insular spot may only be a local upheaval, like the Sandwich Island volcanoes. But I am endeavouring to prove that there has been upheaval, and not all subsidence, in the Southern Pacific (the present accepted belief). It looks as if there has been a tilting, the islands along the 20th parallel of south latitude rising, and those at the equator and to the north of it sinking. Then, a crumpling is evidently taking place between Tahiti and South America, the Andes rising slightly and the ocean-bed sinking slightly, the Paumotus being proof of the upheaval being all old coral. Of course, I do not doubt a local slickenside action at any one spot, such as occurred at the Hanmer Plains, in New Zealand, or at Tacoma quite lately, on the North Pacific coast of America, when 600 ft. of docks belonging to the Northern Pacific Railway Company disappeared into the bay. The local subsidences are common in all volcanic regions, and easily understood. But what I am now pointing out are the evidences of a former bulging-out of the earth's crust some 200 ft. to 250 ft. in this particular ocean-area. Nor do I think that any particular harm at the time was done by such a displacement of the water. The tidal wave formed by the movement would have been very serious certainly, and injurious to any native peoples then inhabiting the shores of the ocean near this area, but I doubt whether the peoples surrounding the Indian or Atlantic Oceans would have been much affected by it.
Mr. J. P. Russell, of Wangaimoana, Palliser Bay, New Zealand, pointed me out the spot where an anvil of his had been carried up by the tidal wave (caused by the earthquake here in 1854) some 30 ft. above high-water mark. I dare say
an earthquake such as that of 1854 would form as big a tidal wave as the great and general former upheaval I refer to in the islands of the Pacific.
In the boat-cove at the entrance to Vavau Harbour I saw fractures in the coral caused by upheaval, but these may only have been local. The terraces at Cape Quiros, in Espiritu Santo (New Hebrides), should be counted, as these terraces may represent successive upheavals.
The following is the account of the Tacoma disaster: “More complete details relative to the Tacoma disaster are given in a Reuter's telegram dated Tacoma, Washington, 29th November. A mysterious accident which resulted in great damage to property occurred here last night. At 11 o'clock a loud roaring was heard, like that preceding the advance of a tidal wave, and 600 ft. of the docks suddenly disappeared into the bay. Two steamers were disabled and sunk. The ground in the vicinity subsided to the extent of 6 in. to 1 ft., causing a panic and stampede among the crowd which had collected in the vicinity. The cattlepens of the Northern Pacific Railway, and the company's offices, besides a freight-house 1,400 ft. in length, collapsed, the last mentioned catching fire. Various theories are advanced as to the cause of the disaster. The steamboat men maintain that it was due to a tidal wave 25 ft. in height, while others assert that, owing to a submarine land-slide, a great fissure or hole was formed beneath the bay, causing the docks to be swallowed up. Two lives were lost.”
I ought, perhaps, now to refer to Easter Island. We all know of the stone images there, 5 ft. to 37 ft. high, but usually 15 ft. to 18 ft. These are all cut out of a grey compact lava found in the crater of Hotuiti, at the east end of the island, where there are still many in an unfinished state. Their shape is the human trunk, terminating at the hips, the arms close to the sides, the hands sculptured in low relief, and clasping the hips. The head is flat, and the top of the forehead cut off level, so as to allow the crown, which is made of red tuff (found in the Te Rano Kao crater), to be put on. The face is square, massive, and sternly disdainful in expression, the aspect always upwards. Easter Island is volcanic, and has numerous extinct craters rising from different parts of the island, none of which have been active for a long time. The red tuff found in the Te Rano crater, from which the crown of the images are made, shows previous submarine volcanic origin; calc. tuff—which I suppose this red tuff to mean—being a mineral nearly identical with limestone and marble. The statement of the present inhabitants of Easter Island that their ancestors cut these images need not be credited. As already mentioned, my opinion is that the images were cut
by a race of people previous to the special local migration of the present inhabitants. I know of no race of islanders in the Pacific now acquainted with sculpture; neither do they possess even the tools with which they could do the work.
There is an exception, perhaps, to these two statements—viz., the arragonite money of Uap (or Yap), in the Carolines, and the Spaniards may have taught some of the Western Pacific islanders, since the sixteenth century, to roughly carve in coral. But the extraordinary money mentioned is composed of large discs of arragonite, often of great size; 6 ft. in diameter, 12 in. thick, and about 3 tons in weight are not uncommon dimensions. It is not used as a medium of exchange, but for purposes of ostentation. The arragonite is brought from a quarry in the Harbour of Malakal, at Korror Island, in the Palao or Pelew Group.
At the Duke of York and New Britain Islands it was the custom for a chief to place all his treasures before a visitor, and after inspection to have them put away. Thus several large coils of cowry money, about the size of lifebuoys, were placed before the Rev. Messrs. Brown and Fletcher at Blanche Bay when opening the first mission to those islands in 1875. These islands are about thirteen hundred miles from Uap, not an excessive distance for a canoe voyage in the Pacific. It would be well if some officer of our warships visiting the Carolines would inform us how this arragonite money is cut and removed from the quarry.
The trinolith and Langiis at Tongatabu (of which I present photographs) were cut from the coral reef, I believe, as the stones are not far from shore. (I am waiting Mr. A. W. Mackay's paper for a full and minute description of these ruins.) Arragonite is a mineral essentially consisting of carbonate of lime, and much like calcareous spar. The two minerals only differ in their form of crystallization. The rhombic prisms of arragonite are easily divided by the hammer, so that there should be little difficulty in quarrying them. Arragonite is a mineral found usually in volcanic districts, and in the neighbourhood of hot springs. Its crystals are sometimes prisms shortened into tables, which this money resembles. It appears to be the product of a crystallization taking place at a higher temperature than that in which calcareous spar is produced, showing great submarine volcanic action in days gone by at Uap. I should consider that the coral-polyp first deposited the lime, great subsidence and followed by volcanic action subsequently breaking up and converting the reef into columns of basalt, calcareous spar, and arragonite.
Mr. F.J. Moss, in his book, “Through Atolls and Islands in the Great South Sea,” writes of Ponape (or Ascension
Island, the largest of the Seniavine Group in the Carolines) and its neighbouring islets “as being a number of volcanic islands varying in size, representing the mountain-tops of an ancient land,” quite forgetting that the basaltic columns of which the ruins at Ponape are composed are really a variety of volcanic lava formed from lime. The ancient mountains must first of all have the lime deposited upon them, then have been subjected to great volcanic action, which melted them, and afterwards threw them up from the sea. Evidences show that these islands are now sinking again, which looks to me as if the bed of the Pacific ever since the globe cooled has been the seat of a constant and steady deposit of lime and subsequent great volcanic action, including upheaval and subsidence.
I might mention here that Ponape itself rises some 2,860 ft., its shores and hillsides strewn with loose blocks of basalt, many of them perfect hexagonal prisms of considerable size. Mr. Moss considers its summit “as probably to have formed the backbone of an ancient great mountain-range of the submerged continent.” I refer members to his interesting work. Yet he tells us “that so thickly is the place strewn, so numerous are the basaltic blocks, and so extensive an area do they cover, that it looks as if the whole island had been at one time terraced and cultivated, and that these rocks and prisms are the ruins of the terraces washed or fallen from the hills to the shore below.” But the basaltic columns forming the walls of the great temple ruin at Ponape show little or no wear from water. Their rhomboids and angles are still intact, which makes me think that the volcanic action was submarine, and that subsequent upheaval tumbled the columns and broke them up as they now are found. Moreover, the particular islet upon which this great temple is found, like many of the other islets near it, is embanked with massive walls of the same style as the building. “These careful embankments, the great walls, and the solemn silence gave to the whole the appearance of a city dead and deserted now, but with canals once crowded with canoes filled with devotees eager to attend the savage rites and sacrifices of which the ruined mass before us may have been the sacred scene.” Ancient Mexican history and rites are recalled to mind by this extract. The embankments forming these canals show that the sea was encroaching when they were built. Also the fact that the canals are still wadable shows either that they could not have been embanked so many centuries ago or the extreme stationary condition of sea- and land-level for the past 3,500 years in that locality.
There is little doubt to my mind that colonies from ancient Mexico and Peru voyaged westward into the Pacific and left
traces of their handiwork at Easter Island and on Tonga. The Carolines doubtless were colonised from Asia.*
Again, Mr. Moss says, “The rude character of the structures is apparent. Not a vestige of art or workmanship of any kind is to be seen.” Now, the Langiis at Tongatabu show sculpture, as do the images at Easter Island.
At Tele, forming one of the Ualau or Strong Island Group (Ualau rises 2,000 ft., and is a basaltic island), are similar interesting ruins built of enormous blocks of basalt, showing that the people who shifted them about knew how to handle great weights, like the pyramid-builders in Mexico, Peru, and Egypt, and those who erected the stone ruins we find at Stonehenge or in northern France.
There are also several artificial canals and a canoe-harbour at Tele. These artificial canals show an acquaintance with the ancient canal system of Mexico and Peru, and that the migration of people who built them may have come direct from America. The ruins in Tele are stated by the natives to have been built by the former inhabitants partly for their defence and partly in honour of the dead, the large blocks of stone being brought from the main island on rafts. This, again, shows an acquaintance with the manner the red-granite blocks of Syene in Upper Egypt were anciently rafted down the river to Lower Egypt in flood-time, also with the way the Assyrians rafted great weights down their rivers. I do not think the present inhabitants of any of the Carolines know how to remove these heavy weights. A great weight is sometimes moved in the islands by rolling or pushing it into deep water, lifting it and fastening it under two strong canoes, and then sailing or paddling it to any required distant point. But this, again, only proves an acquaintance with ancient raft-movement, as it were.
Captain C. A. Bridge, of H.M.S. “Espiègle,” read an excellent paper, I believe, upon these ruins before the Royal Society, but I have not seen it. All that I wish to show is the part played by volcanic action in their origin.
[Footnote] * We really have to go back at least to the pyramid-builders (3,500 years ago) to reach an age where the people executed such works as we find at Tongatabu, Easter Island, and the Carolines. The latter, however, appear to be rude and cyclopean, another proof of the lapse of the thirty-five centuries of human time. Geological time (millions of years) I am not referring to at all, as my task is only to record the surface facts as I find them now in the Pacific. If the coral-polyp is nature's scavenger, and keeps the waters of the ocean pure by extracting the excess of lime within equatorial limits, fixing it there in the form of coral reefs, there must, I suppose, be some method of redistribution or the equatorial regions would soon be all lime. Upheaval and subsidence resulting from great volcanic action may be the methods nature employs to melt and redistribute this excess of lime and keep everything equal on the planet.
The Hogulu group of islands, in the Carolines, is composed of ten lofty basaltic islands and numerous coral islands enclosed in a vast lagoon like a large lake in the sea. Yap, or Uap, or Guap is also of volcanic origin.
Asking pardon for this digression, I now proceed onwards to the eastern Pacific, so as to finish this portion of my subject.
Some of the Paumotus are rising, some sinking, some in a state of rest. Henderson Island is 80 ft. high. Pitcairn and the Gambiers rise to 1,000 ft. Osnaburg Island appears to have changed since 1790 from a “reef of sunken rocks” to an island fourteen miles long; whilst Archangel Island (20° 29′ S.) appears to have sunk out of sight since 1606. Actual volcanic action is most peculiar. It really appears to delight in confining itself (in the one given line) to one spot or pipe at a time, striking a blow or thump from below to “knock out,” as it were, one identical spot; which, if weak enough, “gives” to the imprisoned giant; and we have an elevation or a crater. At sea this thump from below strikes a vessel as if she had gone crash upon a rock. Quite recently a vessel sailing from San Francisco to Japan met with such an experience in the northern Pacific, and it made the crew dazed and sick. The greater the pressure of water the more the imprisoned giant likes to assert itself; but directly it meets with no resistance it acts quite gently, and expands its force in slight elevations above the sea. But I regard volcanic phenomena as the great ultimate friend of man, notwithstanding any immediate damage they may do.
Many of these Paumotu Islands descend sheer 1,500 ft. to 4,000 ft. within 1,000 yards of the reef. Aurora Island (15° 48′ S.) is an uplifted coral island about 230 ft. high, with the usual perpendicular sides found all along this line, and nowhere else that I know of on the planet except in Possession Island, in the Antarctic, where Sir James C. Ross landed in 1841. The Tongan Islets are positively square, having flat tops and straight sides. Of course, there are many coasts with perpendicular cliffs, but what I wish to say is that these straight-up-and-down islands show upheaval, and not subsidence.
Of course, a vast deal of geological work is required to be done in the Pacific, now the very home of volcanic activity, as it were, of this planet—here and in the antarctic region. In Appendix B I give a brief account of the antarctic volcanoes from a paper by Captain Borchgrevinck, in order that all the information I can collect of volcanic action within the sphere of the Pacific Ocean, as it were, may be collected in one paper for the use of future observers.
The Marquesas lie nine hundred miles to the north-east of
the Society Islands, nearly midway between them and the equator, being situated between the parallels of 8° and 11° S. and the meridians of 138° and 141° W. They have a warmer climate than Tahiti, and are all mountainous and volcanic, rising to upwards of 5,000 ft. above the sea (Magdalene, 3,675 ft.; Santa Christina, 3,280 ft.; Adams Island, 4,042 ft.; and Masse Island, 2,000 ft. high). The mountain-peaks are extremely broken and rugged, and the centres of some of the islands are occupied by piles of rocks of most fantastic shape. The volcanic precipices in many places extend abruptly down to the sea, presenting barren walls of black and naked lava; but the intermediate valleys are singularly fertile and picturesque, and are copiously watered by streams which descend in numerous cascades, one of which (in Nukahiva) is 2,000 ft. high, and is amongst the most beautiful in the world. They have no active volcanoes, and do not appear to be subject to earthquakes.
From Angas's “Polynesia” I also extract certain remarks upon active volcanoes in the Pacific; also an extract from Miss Bird's “Hawaiian Archipelago” (see Appendix A).
I refer briefly to the Sandwich Islands. On the 24th February, 1877, a slight shock of earthquake was felt at Kaavoloa, Hawaii, and steam was observed to be rising from the sea off Cocoanut Point. On visiting the spot it was found that lumps of porous lava, some nearly a cubic foot in size, were rising to the surface, when, on the contained gas escaping, they sank again. At the time of the earthquake a crack opened in the ground from Cocoanut Point in an east-south-east direction, extending for more than a mile, in some places 4 in. broad and 50 ft. deep. (This, again, shows the east-south-east trend. I have sometimes in this paper referred to the trend as south-east and north-west: I believe I should be more correct in saying east-south-east and west-north-west.)
Mauna Haleakala, on the Island of Maui, is somewhat like Mauna Kei, in Hawaii. The craters upon it are inactive, the natives having no tradition of any eruption.
Space does not permit me to refer to the phenomena in the various other islands of the Sandwich Group. Oahu (on which is Honolulu) is the principal island of the group, and the extensive plain on which that city stands is purely volcanic. About three miles north-west of Honolulu there is a remarkable circular salt-water lake, about half a mile in diameter, so impregnated with salt that twice every year the natives take out large quantities of fine, hard, clear, crystallized salt, which furnishes a very valuable article of commerce. At the time of the visit of the United States Exploring Expedition it was believed by the natives to be fathomless, but on examination by Commodore Wilkes it proved to be only
18 ft. deep. I mention this now as I have often heard of other lakes in the Pacific believed by the natives to be similarly fathomless.
It will be noticed that the Sandwich Island volcanoes are quite outside of my three lines of phenomena. But Kilauea may only be a huge safety-valve in this particular portion of the earth's crust, showing a great and permanent fault near it. That it has long been so the immense height of the volcanic lava, cinder, and ash heap forming the mountain (nearly 32,000 ft.), with a base of a hundred miles in diameter, proves; so that this safety-valve must have retained this one escape for many thousands of years; or it may be that the whole bed of the ocean for more than a thousand miles round the group has been slowly subsiding, and that the volcanoes on the Sandwich Group, and Cotopaxi and others in Central America, are safety-valves. Certainly the islands in the Pacific on and immediately to the north of the equator, as I of have pointed out, have been also slowly subsiding. The result of this subsidence has been upheaval along the 20th parallel of south latitude, as the evidences show.
I might also point out that the trend of the Sandwich Group, south-east to north-west, somewhat contradicts my theory of islands north of the equator trending south-west to north-east, like the Japan, Kurile, and Aleutian Islands.
I am particular in giving members all the information I can upon this subject, principally in the southern Pacific (without making detailed reference to the New Zealand craters, which more able observers have described), so that the heights and distances of the various active and extinct volcanoes from each other may be seen almost at a glance by any persons studying the map of the ocean. It would be necessary to examine the records taken by the “Challenger” and other expeditions as to the depths of the Pacific Ocean between the different groups of islands. It is a mistake to suppose that there are vast stretches of ocean-bed between these groups, because that is not generally the case by any means. For the fixity of all the continents and oceans'; the limitation of the supposed great glacial epochs and, ice regions almost to their present position; the fixity of the poles and the equator from the original setting of the planet after cooling to the positions we find them now, would follow as corollaries to my present doubt of the former existence of a great southern continent in the Pacific. But why the shores of the Pacific Ocean and its central southern bed should be subject to so much volcanic action is remarkable. We find few such phenomena around the shores of the Atlantic or Indian Oceans The fact that active volcanoes are confined within a short distance of sea-coasts might show a weakness in the
crust of the earth where the great sea-beds join the continents. But I do not see how this weakness could extend right across the arch in the crust of the earth under the great sea-beds from 40° S. latitude to 50° N. latitude, yet it is known that the great earthquake of Lisbon in 1755 did shake such an arch of the earth's crust over an area of 700,000 miles.
This, however, is a question to be hereafter considered. My present task is to set down the actual facts as I find them in the Pacific. I have thought it right to add to the two lines of volcanic action I first purposed pointing out the line of upheaval along the 20th parallel of south latitude, from the Loyalty Islands to the Cook Group, as well as the other facts collected. I have not seen them specially referred to by any other observer before. Huge active volcanoes exist in Central America, the Sandwich Islands, Vulcan Island, and New Guinea. With Mount Hecla near the North Pole, and Mounts Erebus and Terror (and other active volcanoes in Graham Land) near the South Pole, the Pacific volcanoes, with Vesuvius and Etna in the Mediterranean, are nearly the only great safety-valves the planet now possesses. Evidences of extinct volcanoes are abundant, but these are now far removed from sea-water.
The matter has its practical side, too, seeing that the market need never be short of sulphur whilst there are such great deposits of that mineral in Tanna or Ambrym in the New Hebrides, or at the Mother and Two Daughters in New Ireland, &c. The cultivators of the grape-vine in Australia use hundreds of tons of sulphur. They will find plenty in the different spots I have named.
Our own White Island, off Poverty Bay, is still in a state of volcanic activity, and must be regarded as the summit of a crater but little elevated above the sea. It emits from time to time volumes of white smoke. It produces, as I have said, a great quantity of sulphur. Several cargoes have been sent to Europe, and realised £8 a ton. It is very pure, containing 90 per cent.
The intermittent action of volcanic energy referred to is noticed in nearly all active volcanoes and geysers. It is very marked at Tanna, and in some of our New Zealand geyser-fountains the discharge is very regular as to time. There is, indeed, one geyser in our hot-lake district so regular in its discharge that I think it is called the “twelve-minute geyser” (eight to ten minutes at Tanna, and ten to fifteen minutes at Ambrym).
The crater at Cotopaxi is situated in latitude 0° 41′ S. and longitude 78° 42′ W., at a height of 19,493 ft. above the present level of the Pacific Ocean, showing that once a safety-valve is formed the internal fires keep as much as possible to
the one pipe. Extinct volcanic areas may therefore be regarded as practically done and finished with, having performed their part in the economy of the planet.
The earth, perhaps, does not require so many safety-valves now as formerly, and volcanoes will gradually lessen in number. From their present number (270 to 300) it will take, I should think, many million years for their activity to cease; for it is evident that, as it has taken so long a period of time for the extinct volcanoes to assist in the formation of the fixed continents, a similar period may be granted to the present active cones to perform their work and die. Sea-water is doubtless the primary cause of volcanic activity, but there has also to be taken into account the slight annual shrinking of the planet itself, forcing to the surface a small amount of inner material in the form of lava, dust, pumice, and volcanic ash.
The Sandwich Islands Phenomena.
The largest and most important burning mountains at present in a state of activity in the Polynesian Islands are those which occur in the Sandwich Group. One of these, the volcano of Kirauea (Kilauea), in the Island of Hawaii, is especially worthy of notice. Indeed, the whole island, covering a space of four thousand square miles, from the summits of its lofty and snow-clad mountains, some 14,000 ft. above the sea, down to the beach, is, according to the observations of geologists, one complete mass of lava and other volcano substances in different stages of decomposition. Perforated with innumerable apertures in the shape of craters, the island forms a hollow cone over one vast furnace, situated in the heart of a stupendous submarine mountain, rising from the bottom of the sea.
The great volcano of Kirauea, or Kireueanui (Kilauea) as it is called by the Sandwich Islanders, is situated about twenty-five miles inland from the south-east coast of Hawaii, and nearly equidistant between the two great mountains called Mauna Kea and Mauna Roa, the elevation of the former of which is estimated to be 13,645 ft., whilst that of the latter exceeds 14,000 ft. This crater was first visited and described by the Rev. W. Ellis, who made the ascent in 1823. In his graphic and interesting narrative he thus describes the scene presented to his view on reaching the edge of the great crater, after a toilsome ascent through regions of lava and volcanic sand: “About 2 p.m. the crater of Kirauea suddenly burst upon our view. We expected to have seen a mountain with a broad base and rough indented sides, composed of
loose slags or hardened streams of lava, and whose summit, would have presented a rugged wall of scoria, forming the rim of a mighty cauldron; but instead of this we found ourselves on the edge of a steep precipice, with a vast plain before us, fifteen or sixteen miles in circumference, and sunk from 200 ft. to 400 ft. below its original level. The surface of this plain was uneven, and strewed over with large stones and volcanic rocks, and in the centre of it was the great crater, at a distance of about a mile and a half from the walls of the precipice on which we were standing. Our guides led us round towards the north end of the ridge, in order to find a place by which we might descend to the plain below. The steep down which we scrambled was formed of volcanic matter, apparently a light-red and grey kind of lava, vesicular, and lying in horizontal strata, varying from 1 ft. to 40 ft. in thickness. In a small number of places the different strata of lava were also rent in perpendicular or oblique directions from the top to the bottom, either by earthquakes or other violent convulsions of the ground connected with the action of the adjacent volcano. After walking some distance over the sunken plain, which in several places sounded hollow under our feet, we at length came to the edge of the great crater itself, where a spectacle sublime and even appalling presented itself before us. Immediately before us yawned an immense gulf, in the form of a crescent, about two miles in length, from north-east to southwest, nearly a mile in width, and apparently 800 ft. deep. The bottom was covered with lava, and the south-western and northern parts of it were one vast flood of burning matter, in a state of terrific ebullition, rolling to and fro its fiery surge and flaming billows. Fifty-one conical islands, so to speak, of varied form and size, containing so many craters, rose either round the edge or the surface of the burning lake. Twenty-two of them constantly emitted columns of grey smoke or pyramids of brilliant flame; and several of these at the same time vomited from their ignited mouths streams of lava, which rolled in blazing torrents down their black indented sides into the boiling mass below. The grey and calcined sides of the huge crater before us; the fissures which intersected the surface of the plain on which we were standing; the long banks of yellow sulphur on the opposite side of the abyss; the vigorous action of the numerous small craters on its borders; the dense columns of vapour and smoke that rose at the north and south ends of the plain; together with the ridge of steep rocks by which it was surrounded, rising probably, in some places, 300 ft. or 400 ft. in perpendicular height, presented an immense volcanic panorama, the effect of which was greatly augmented by the constant roaring of the vast furnaces below.” At night the grandeur of the scene
reached its climax. “The dark clouds and heavy fog that after sunset had settled over the volcano gradually cleared away, and the fires of Kirauea, darting their fierce light athwart the midnight gloom, unfolded a sight terrible and sublime beyond all we had seen. The agitated mass of liquid lava, like a flood of melted metal, raged with tumultuous whirl. The lively name that danced over its undulating surface, tinged with sulphurous blue or glowing with mineral red, cast a broad glare of dazzling light on the indented sides of the insulated craters, whose roaring mouths, amidst rising flames and eddying streams of fire, shot up at intervals, with very loud detonations, spherical masses of fusing lava or bright ignited stones. The dark, bold outline of the perpendicular and jutting rocks around formed a striking contrast with the luminous lake below, whose vivid rays, thrown on the rugged promontories and reflected by the overhanging clouds, combined to complete the awful grandeur of the scene.”
From Miss Bird's “Hawaiian Archipelago” I extract the following description of the great lava-flow of Kilauea of the 2nd April, 1868 (I think it only right to include it here): “I could fill many sheets with what I have heard, but must content myself with telling you very little. In 1855 the fourth recorded eruption of Mauna Loa occurred. The lava flowed directly Hilo-wards, and for several months, spreading through the dense forests which belt the mountain, crept slowl shorewards, threatening this beautiful portion of Hawaii with the fate of the cities of the plain. Mr. C. made several visits to the eruption, and on each return the simple people asked how much longer it would last. For five months they watched the inundation, which came a little nearer every day. Should they fly or not? Would their beautiful homes become a waste of jagged lava and black sand, like the neighbouring district of Puna, once as fair as Hilo? Such questions suggested themselves as they nightly watched the nearing glare, till the fiery waves met with obstacles which piled them up in hillocks, eight miles from Hilo, and the suspense was over. Only gigantic causes can account for the gigantic phenomena of this lava-flow. The eruption travelled forty miles in a straight line, or sixty including sinuosities. It was from one to three miles broad, and from 5 ft. to 200 ft. deep, according to the contours of the mountain-slopes over which it flowed. It lasted for thirteen months, pouring out a torrent of lava which covered nearly three hundred square miles of land, and whose volume was estimated at 38,000,000,000 cubic feet! In 1859 lava-fountains 400 ft. in height, and with nearly equal diameter, played on the summit of Mauna Loa. This eruption ran fifty miles to the sea in eight days,
but the flow lasted much longer, and added a new promontory to Hawaii. These magnificent overflows, however threatening, had done little damage to cultivated regions, and none to human life; and people began to think that the volcano was reformed. But in 1868 terrors occurred which are without precedent in island history. While Mrs. L. was giving me the narrative in her graphic but simple way, and the sweet-wind rustled through the palms, and brought the rich scent of the ginger-plant into the shaded room, she seemed to be telling me some weird tale of another world. On the 27th March (five years ago) a series of earthquakes began, and became more startling from day to day, until their succession became so rapid that ‘the island quivered like the lid of a boiling pot nearly all the time between the heavier shocks. The trembling was like that of a ship struck by a heavy wave.’ Then the terminal crater of Mauna Loa (Mokua-weoweo) sent up columns of smoke, steam, and red light; and it was shortly seen that the southern slope of its dome had been rent, and that four separate rivers of molten stone were pouring out of as many rents, and were flowing down the mountain-sides in diverging lines. Suddenly the rivers were arrested; and the blue mountain-dome appeared against the blue sky without an indication of fire, steam, or smoke. Hilo was much agitated by the sudden lull. No one was deceived into security, for it was certain that the strangely pent-up fires must make themselves felt. The earthquakes became nearly continuous; scarcely an appreciable interval occurred between them; the throbbing, jerking, and, quivering motions grew more positive, intense, and sharp; they were vertical, rotary, lateral, and undulating, producing nausea, vertigo, and vomiting. Late in the afternoon of a lovely day, 2nd April, the climax came. ‘The crust of the earth rose and sank like the sea in a storm.’ Rocks were rent, mountains fell, buildings and their contents were shattered, trees swayed like reeds, animals were scared and ran about demented, men thought the judgment had come. The earth opened in thousands of places, the roads in Hilo cracked open, horses and their riders and people afoot were thrown violently to the ground; ‘it seemed as if the rocky ribs of the mountains and the granite walls and pillars of the earth were breaking up.’ At Kilauea the shocks were as frequent as the ticking of a watch. In Kau, south of Hilo, they counted three hundred shocks on this direful day; and Mrs. L.'s son, who was in that district at the time, says that the earth swayed to and fro, north and south, then east and west, then round and round, up and down in every imaginable direction, everything crashing about them, 'and the trees thrashing as if torn by a strong rushing wind.'
He and others sat on the ground bracing themselves with hands and feet to avoid being rolled over. They saw an avalanche of red earth, which they supposed to be lava, burst from the mountain-side, throwing rocks high into the air swallowing up houses trees, men, and animals, and travelling three miles in as many minutes, burying a hamlet with thirty-one inhabitants and five hundred head of cattle. The people of the valleys fled to the mountains, which themselves were splitting in all directions, and, collecting on an elevated spot, with the earth reeling under them, they spent the night of the 2nd April in prayer and singing. Looking towards the shore they saw it sink, and at the same moment a wave, whose height was estimated at from 40 ft. to 60 ft., hurled itself upon the coast and receded five times, destroying whole villages, and even strong stone houses, with a touch, and engulfing for ever forty - six people who had lingered too near the shore. Still the earthquake continued, and still the volcano gave no sign. The nerves of many people gave way in these fearful days. Some tried to get away to Honolulu; others kept horses saddled on which to fly, they knew not whither. The hourly question was, What of the volcano? People put their ears to the quivering ground and heard, or thought they heard, the surgings of the imprisoned lava-sea rending its way among the ribs of the earth. Five days after the destructive earthquake of the 2nd April the ground south of Hilo burst open with a crash and roar which at once answered all questions concerning the volcano. The molten river, after travelling underground twenty miles, emerged through a fissure two miles in length with a tremendous force and volume. It was in a pleasant pastoral region, supposed to be at rest for ever, at the top of a grass-covered plateau covered with native and foreign houses, and rich in herds of cattle. Four huge fountains boiled up with terrific fury, throwing crimson lava, and rocks weighing many tons, to a height of from 500 ft. to 1,000 ft. Mr. Whitney, of Honolulu, who was near the spot, says, ‘From these great fountains to the sea flowed a rapid stream of red lava, rolling, rushing, and tumbling like a swollen river, bearing along in its current large rocks that made the lava foam as it dashed down the precipice and through the valley into the sea, surging and roaring throughout its length like a cataract, with a power and fury perfectly indescribable. It was nothing else than a river of fire from 200 ft. to 800 ft. wide and 20 ft. deep, with a speed varying from ten to twenty-five miles an hour.’ This same intelligent observer noticed as a peculiarity of the spouting that the lava was ejected by a rotary motion, and in the air both lava and stones always rotated towards the south. At Kilauea I noticed that the lava was ejected in a southerly direction.
From the scene of these fire-fountains, whose united length was about a mile, the river in its rush to the sea divided itself into four streams, between which it shut up men and beasts. One stream hurried to the sea in four hours, but the others took two days to travel ten miles. The aggregate width was a mile and a half. Where it entered the sea it extended the coast-line half a mile, but this worthless accession to Hawaiian acreage was dearly purchased by the loss, for ages at least, of 4,000 acres of valuable pasture land, and a much larger quantity of magnificent forest. The whole east shore of Hawaii sank from 4 ft. to 6 ft., which involved the destruction of several hamlets and the beautiful fringe of cocoanut-trees. Though the region was very thinly peopled, two hundred houses and a hundred lives were sacrificed in this week of horrors; and from the reeling mountains, the uplifted ocean, the fiery inundation, the terrified survivors fled into Hilo, each with a tale of woe and loss. The number of shocks of earth-quake counted was two thousand in two weeks, an average of a hundred and forty a day; but on the other side of the island the number was incalculable.”
Extracts from a Paper by Captain C. G. Borchgrevinck.
Already the first sight of Victoria Land convinces one that it is of volcanic origin. The volcanoes of Victoria Land show a tendency to follow the same line. From Mount Sabine to Mount Melbourne the trend is south-southwesterly. Mount Erebus and Mount Terror lie almost due south of Mount Sabine. Further north from Mount Sabine the great earth-fold, on the septum of which this chain of volcanoes is situated, probably bends a little westward, as shown partly by the surroundings partly by the position of Balleny Island. North-west of Balleny Islands the great fold trends perhaps to the knotting-point between the Tasmanian axis of folding and that of New Zealand, the former perhaps running through Royal Company Island and Macquarie Island. The knotting-point would probably be somewhere (approximately) near the intersection of the 60th parallel of south latitude, about the 150th meridian of longitude east from Greenwich. It would just join the line of extinct volcanoes along East Australia on the west, and perhaps the active volcanic zone of the North Island of New Zealand, or, at all events, the fold which bounds that continent, on the east.
Traced in the opposite direction the volcanic zone probably runs through Seal Islands, the active volcanoes of
Christensen and Sarsee, and through Mount Haddington, an extinct volcano in Trinity Land, to Paulet and Bridgman Islands' active volcanoes. The volcanic zone bends easterly from here on account of the easterly trend in the fold, which appears to make a loop towards South Georgia before it swings back towards Cape Horn. That there is a real easterly trend in the earth-fold at Trinity Land and the South Shetlands is proved by the observations made by the “Astrolabe” and “Zélée” expedition, which record a strike in a north-north-east and south-south-west direction to the greyish-white limestones and phyllite-schists at the South Orkneys. Toward Cape Horn from near South Georgia the fold probably trends west-north-westerly, then follows an approximately meridional direction parallel with the chain of the Andes.
It may be noted, however, that, whereas the Erebus chain of Victoria Land is on the east side of the fold, the Christensen-Bridgman group are apparently on the opposite side. This may be due to the fact that at the latter locality the eastern slope of the fold is steeper than the western, as seems probable from the presence of the deep ocean abyss east of Graham Land, as shown on Dr. Murray's map. It is probable, therefore, that the volcanic chain of Victoria Land will continue towards the south pole, probably bending somewhat to the eastward, and will thence change its position to the fold on the other side of the antarctic continent, so as to run through the Christensen-Bridgman lines of volcanoes. In any case it is almost certain that high land, covered, of course, more or less by snow and glaciers, will be found at the south pole.
The honour of being the first man to discover the antarctic continent probably belongs to Captain James Cook, who, in the year 1772, reached latitude 71° 10′ S. in longitude 106° 54′ W., where he sighted the great ice-barrier which formed the seaward boundary of Antarctica. Speaking of this discovery, Sir James Clark Ross says, “I confidently believe that the enormous mass of ice which bounded his view when at his extreme south latitude was a range of mountainous land covered with snow.” In 1819 William Smith, in the brig “William,” discovered the archipelago of the South Shetlands, south of Cape Horn. In 1820–23 Weddell visited the South Shetlands, including the active volcano Bridgman. Powell, the discoverer of the South Orkneys, visited the volcanic island of Bridgman in 1882, and found it to be at that time 200 ft. high. Weddell, who visited it during the following year, estimates its height at 400 ft., and describes the island as being of sugar-loaf shape, whereas at the time of Powell's visit there was a crater on the west side
of the island. Weddell penetrated to 74° S. in 1823, thus attaining a higher latitude than Captain Cook, but he saw no land anywhere in that neighbourhood. In 1831 Biscoe, in the brig “Tula,” discovered Enderby Land. In 1839 Balleny discovered Balleny Islands, a volcano 12,000 ft. high, and adjoining it the active volcano of Buckle Island. In 1839 the important French expedition under Dumont D'Urville explored the South Shetlands. In 1840 Commander-Wilkes, in the U.S.A. corvette “Vincennes,” discovered Wilkes Land. In January, 1841, Sir James Clark Ross made his memorable discovery of Victoria Land. With the object of trying to find the south magnetic pole, as he had already found the north magnetic pole, he forced his well-fortified ships through the pack-ice which he encountered in latitude about 67° S., and longitude 17 4 ½° E. It was a very formidable pack. In four or five days, however, he forced his way through it and entered comparatively open water—being a great ocean-pool about six hundred miles in diameter. Bounding this on the west was the magnificent chain of snow-clad volcanoes of Victoria Land. Ross traced the coast for five hundred miles southwards, until he encountered the great ice barrier terminating seawards in a sheer wall of ice from 180 ft. to 200 ft. high. His dredging showed that marine forms of animal life, especially Polyzoa, were abundant right up to the edge of the great ice barrier. Ross states that on the 19th January, 1841, when off the coast of South Victoria Land, in latitude 72° 31′ S., longitude 173° 39′ E., the dredge was put over in 270 fathoms water, and after trailing along the ground for some time was hauled in.
In 1874 H.M.S. “Challenger” visited the neighbourhood of the supposed Termination Land of Wilkes. In 1893—94 the whaler “Jason,” with Captain Larsen, visited the northwestern portion of Antarctica.
The important discovery was made by Dr. Donald of Lower Tertiary rocks within the fossil shells—Cucullæa, Natica, and Cytherea, in sitû—at Cape Seymour. Fossil wood was found imbedded in the Tertiary rocks at a level of 300ft. above the sea. A new active volcano, named by Captain Larsen “Christensen Volcano,” was discovered in latitude 65° 5′, longitude 58° 40′ W. On the sketch-chart accompanying Captain Larsen's paper another active volcano is shown also, Windberg Volcano, and the four Seal Islands, all of which are considered to be of volcanic origin, if not dormant or extinct volcanoes.