WITHIN a few miles of Antsìrabé are two crater lakes. The nearer and larger of these is called Andraikìba, which lies distant about four miles due west. This is a beautiful sheet of water, blue as the heavens in colour, in shape an irregular square, but curving round to the north-west, where it shallows into a marsh, which is finally absorbed in rice-fields. The lake is said to be of profound depth, but the hills surrounding it are not very lofty, rising only about two hundred feet above the surface of the water, from which they ascend steeply. Fish and water-fowl, and crocodiles also, are very abundant in and on its waters.

But the most interesting natural curiosity to be seen in the neighbourhood of Antsìrabé is the crater-lake of Trìtrìva. This is situated about ten miles to the south-west, a pleasant ride of two hours by palanquin. Travelling at first in a westerly direction, the road then turns more to the south-west, and skirts the southern foot of the old volcano of Vòhitra. Passing about a mile or two south of the high ground round the southern shores of the Andraikìba lake, the road gradually ascends to a higher level of country, so that in about an hour and a half’s time we are nearly as high as the top of Vòhitra—probably about five hundred feet. Reaching a ridge between two prominent hills, we catch our first sight of Trìtrìva, now from two to three miles distant in front of us. From this point it shows very distinctly as an oval-shaped hill, its longest axis lying north and south, and with a great depression in its centre, the north-eastern edge of the crater wall being the lowest part of it, from which point it rises gradually southwards and westwards, the western edge being at the centre from two to three times the height of the eastern side. To the north are two much smaller cup-like hills, looking as if the volcanic forces, after the main crater had been formed, had become weaker and so been unable to discharge any longer by the old vent, and had therefore formed two newer outlets at a lower level.

Descending a little from the ridge just mentioned, we cross a valley with a good many scattered hamlets, and in less than half-an-hour reach the foot of the hill. A few minutes’ pull up a tolerably easy slope, perhaps two hundred feet in height, brings up to the top, at the lowest part of the crater edge; and on reaching the ridge the crater of the old volcano and its lake is before us, or, rather, below us. It is certainly an extraordinary scene. The inner sides of the crater dip down very steeply on all sides to a deep gulf, and here, sharply defined by perpendicular cliffs all round it, except just at the southern point, is a rather weird-looking dark green lake far below us, the water surface being probably from two hundred to three hundred feet lower than the point we are standing upon, and consequently below the level of the surrounding country. The lake, exactly shut in by the cliffs of the crater surrounding it, is not blue in colour, like Andraikìba, although under a bright and cloudless sky, but a deep and somewhat blackish-green. It must look, one would suppose, like ink under a stormy sky or in the shadows of evening.

We sit down to rest and try to take in all the details of this novel picture. It is undoubtedly an old volcano we are now looking down into; the spot on which we rest is only a few feet in breadth, and we can see that this narrow knife-edge is the same all round the crater. Outside of it the slope is pretty easy, but inside it descends steeply, here and there precipitously, to the edge of the cliffs which so sharply define the actual vent and, as distinctly, the lake which they enclose. Looking southwards, the crater edge gradually ascends, winding round the southern side, and still ascending as the eye follows it to the western, the opposite side, where the crater wall towers steeply up from two hundred to three hundred feet higher than it does on the east, where we are standing. The lake we judge to be about eight hundred to nine hundred feet long and two hundred to two hundred and fifty feet wide, forming a long oval, with pointed ends. The cliffs which enclose it appear to be from forty to fifty feet in height, whitish in colour, but with black streaks, where the rain, charged with carbonic acid, has poured more plentifully down their faces. These cliffs are vertical and in some places overhang the water, and from their apparently horizontal stratification are no doubt of gneiss rock. In coming up the hill I noticed a few small lumps of gneiss among the basaltic lava pebbles. The strongest feature of Trìtrìva is the sharply defined vertical opening of the vent, looking as if the rocks had been cut clean through with an enormous chisel, and as if they must dip down—as is the case—to profound depths below the dusky green waters. At the northern end of the lake is a deep gorge or cleft, partly filled with bushes and other vegetation. Southward of this, on the eastern side, the cliffs are still lofty and overhang the water, but at about a third of the lake’s length they gradually decrease in height, and at the southern point they dip down to the level of the lake, so that at that part only can the water be approached. On the western side the cliffs keep a pretty uniform height all along the whole length.

So steep is the inward slope of the crater walls that we all experienced a somewhat “eerie” feeling in walking along the footpath at its edge; for at a very few feet from this a false step would set one rolling downwards, with nothing to break the descent to the edge of the cliffs, and then to the dark waters below. Yet there was a strange fascination in the scene, and the variety and contrast and depth of the colours would make the Trìtrìva lake and slopes a striking subject for a painting from many different points along its crater wall. When we arrived, the sun, yet wanting an hour and a half of noon, was still lighting up the grey-white stone of the western cliffs, but the shadows were every minute growing more intense as the sun became more nearly vertical. Far below us was the deep green oval lake; above it, the stratified gneiss cliffs with their black streaks, diversified here and there by patches of bright green bush. Then again from their edges sweep steeply upwards the grey-green sides of the crater, culminating in the lofty western ridge opposite to us. And over all was the blue sky flecked with cirrus clouds; altogether a scene such as I have seen nowhere else in Madagascar, or indeed in any other country.

After fixing in our minds the view from the north-east, we proceeded southwards along the crater edge to the higher part at the south-east, where the view is equally striking, and the depth of the great chasm seems still more profound. Here we waited some time, while most of our men went down to one of the hamlets in the plain to the east to get their meal, in which quest, however, they had only poor success. On expressing a wish to taste the Trìtrìva water, one of our bearers took a glass, and descending by a breakneck path, went to fetch some water from the lake. He was so long away that we were beginning to feel uneasy, but after a quarter of an hour he reappeared with the water, which tasted perfectly sweet and good. He also entertained us with some of the legends which were certain to have grown up about so weird-looking a place as Trìtrìva. Pointing to two or three small trees or bushes growing on the face of the cliffs near the northern point of the lake, he told us these were really a young lad and lass who had become attached to each other; but the hard-hearted parents of the girl disapproving of the match, the youth took his loin-cloth, and binding it round his sweetheart and his own body, precipitated her with himself into the dark waters. They became, so it is said, two trees growing side by side, and they now have offspring, for a young tree is growing near them; and in proof of the truth of this story, he said that if you pinch or break the branches of these trees, it is not sap which exudes, but blood. He appeared to believe firmly in the truth of this story.

He also told us that the people of a clan called Zànatsàra, who live in the neighbourhood, claim some special rights in the Trìtrìva lake; and when any one of their number is ill they send to see if the usually clear dark green of the water is becoming brown and turbid. If this is the case they believe it to be a presage of death to the sick person.

Another legend makes the lake the former home of one of the mythical monsters of Malagasy folk-lore, the Fanànim-pìto-lòha or “seven-headed serpent.” But for some reason or other he grew tired of his residence, and shifted his quarters to the more spacious and brighter lodgings for seven-headed creatures afforded by the other volcanic lake of Andraikìba.

This same bearer assured us that in the rainy season—contrary to what one would have supposed—the water of the lake diminishes, but increases again in the dry season. He told us that there is an outlet to the water, which forms a spring to the north of the mountain. I noticed a white line a foot or two above the surface of the water all round the foot of the cliffs, showing a probably higher level than at the time of our visit. It was popularly supposed to be unfathomable, but some years after my visit the Rev. Johannes Johnson, of the Norwegian Mission, sounded the lake in three places. The deepest portion was found to be at the northern end, where it proved to be four hundred and seventy-four feet in depth.

Walking round to the southern end of the crater edge, the lake, here foreshortened, has a somewhat close resemblance in outline to that of the lake of Galilee, as seen on maps; but I must confess that the first sight of it in its deep chasm made me think much more of the other lake of Palestine, the Dead Sea, in its profound gorge between the Judean hills and the highlands of Moab. After making a slight pencil sketch or two, I proceeded up the far higher saddle-back ridge on the western side. Here the lake seems much diminished in size and lying far down at an awful depth. But a magnificent and extensive view is gained of the surrounding country: the long flat-topped lines of hill to the east running many miles north and south, and surmounted directly east by the two perfect cones of old volcanoes; the peaked and jagged range of Vòlombòrona to the south-east; the enormous mass of Ibity to the south, and then west, a flat region broken by abrupt hills. To the north-west are the thickly populated valleys towards Bétàfo, with many a cup-shaped hill and mountain marking old volcanic vents; and beyond this a high mass of country with serrated outline against the sky, showing the district of Vàvavàto; and finally, coming to due north, is the varied grouping of the hills, which form the southern termination of the central mountain mass of Ankàratra. Between us and these again is the extensive plain of Antsìrabé, with the white walls and gables of the church and the mission buildings plainly visible in the bright sunhsine, although ten or twelve miles distant—altogether, a panorama long to be remembered. From this point also the significance and appropriateness of the name given to the old volcano is clearly seen; for Trìtrìva is apparently a combination of the words trìtry, a word used to describe the ridge on the back of a chameleon or a fish, and ìva, low, deep; so that the name very happily describes the long steep western ridge or crater wall, and the deep chasm sweeping down from it.

It may just be said further, that the slopes of the crater both inside and out are covered with turf, which grows on a dark brown volcanic soil, mingled with rounded pebbles of greenish or purple lava, very compact and close in structure, and containing minute crystals scattered sparingly through it. Occasional blocks of this are found round the edge of the crater wall, and the same rock crops out at many places on the steep inner slopes. I did not notice any vesicular lava or scoria; and at a little homestead not far from the north-eastern foot of Trìtrìva, I was surprised to find the hàdy or fosse dug to twelve or fourteen feet deep almost entirely through the red clay or earth found all through the central regions of the island. The dark brown volcanic soil, here seen in section, appeared to be only eighteen inches deep, with layers of small pebbles. So that the discharge of the volcanic dust and ash appears to have extended only a short distance from the mountain; at least it does not appear to have been very deep, unless, indeed, there has been much denudation. It must be remembered, however, that this point is to the windward side of the hill; probably the volcanic soil is deeper to the west of it. The much greater height of the western wall of the crater is no doubt due to the prevailing easterly winds carrying the bulk of the ejected matter to the west, and piling it up to two or three times the height of the eastern side. After seeing the amount of gneiss rock which must have been blown out of the vent, I expected to have found much greater quantities of it, and in larger blocks, than the very few and small fragments actually seen on the outer slopes. The greater portion, however, is probably covered up under the quantities of volcanic dust and lapilli which were subsequently ejected.

Trìtrìva, it will be evident from this slight sketch, will greatly interest those who have a taste for geology and physical geography; while its peculiar and somewhat awe-striking beauty makes it equally worthy of a visit from the artist and the lover of the picturesque. Certainly it became photographed upon our memory with a distinctness which rendered it a vivid mental picture for many a day afterwards.

Returning northward from Antsìrabé towards the neighbourhood of Itàsy, we have to pass to the westward of the great massif of Ankàratra; and the summits of this mountain mass being the highest points in the centre of the island, a short space must be devoted to a brief description of it. From the capital, Ankàratra is the most prominent object in the landscape to the south-west, rising by easy gradients to about twice the elevation of the general level of Imèrina, and three or four points showing distinctly against the sky, although they are from forty to forty-five miles distant. The highest point is called Tsiàfajàvona (“that which the mists cannot climb”), and is eighty-six hundred and thirty-five feet above sea-level. There is no doubt that the whole mountain is an ancient volcano, for the rock which has been poured out as lava from it is a black olivine basalt. One peak, to the east, consists of mica-trachyte; and at its northern foot there is an exposure of augite-andesite rock. “Seen from Antanànarìvo, the mountain of Ankàratra seems to be one almost uniform mass, but when actually there, it resolves itself into deep ravines, enormous spurs, conspicuous peaks, and isolated or continuous mountain masses. The spurs, which run out like so many fingers in all directions, and to great lengths from the main body of the mountain, do not represent so many lava flows, but have been formed by the numerous streams which have excavated the deep and wide valleys between them.”

The amount of lava that has issued from Ankàratra, says Mr Baron, is truly astounding, reaching in places to a depth of twelve hundred to fourteen hundred feet, and occasionally to as much as two thousand feet. Occasionally the basalt assumes a columnar form; but everywhere the surface of the lava is decomposed into soil. This, and the apparent absence of all craters on and around the mountain, seems to point to a long period having elapsed since the volcano was active, probably several centuries. When on the highest point of the mountain, there appear to be two ranges of summits; which lie in the form of a cross, the intersection being marked by a small cone. On the south-western slopes are considerable remains of forest, which probably in former times covered a large proportion of the present bare highland of the interior of Madagascar. It is by no means easy to get natives to go with one to these lofty points. They are afraid of the vengeance of the spirits of the mountains, who will punish all who dare invade their territories.

In one of the valleys to the west of the Ankàratra massif there is a river called Antsèsika, which is quite lost to sight and sound for about a mile and a quarter. It disappears under a mass of enormous gneiss boulders, which have filled up the valley of the river, so that the stream runs for a considerable distance at an immense depth below the general level. In the upper part of its course, this river passes over a series of grand falls before diving deep into the earth, as just described. Its name of Antsèsika is very appropriate, as it means “that which is thrust in.”

Some members of the extinct fauna of Madagascar (Æpyornis, hippopotamus and crocodile) have been already noticed, but we must here mention other discoveries made within the last few years. About twenty years ago a skull, in a sub-fossil condition, was discovered on the south-west of the island, and proved to be that of a gigantic form of lemuroid animal. This skull is very much larger and longer than those of any existing lemurs (which are fairly globular in shape), and belonged to a creature more like a gorilla in size and strength. More recently, at a place called Ampàsambazìmba, which is five miles north of Itàsy, the remains of a number of species (fourteen or fifteen) of extinct lemuroid animals have been discovered; in fact this spot seems like the burial-ground of a whole fauna now entirely passed away, and probably quite recently; for Dr Standing, who conducted the excavations, thinks that not more than five centuries have elapsed since some at least of these animals were living. Several new species of apparently quite distinct genera have been disinterred; they are mostly larger than any existing lemuroid; and some of them form links between the true monkeys and the lemurs—families of primates now very distinct from each other. Some of these newly discovered creatures seem, from the position of the nostrils, eyes and ears (like those of the hippopotamus), to have been adapted to a partially aquatic life. There is abundant evidence of the former existence of extensive lakes in the surrounding country, where now there is only marsh or dry land. Others of these extinct animals were arboreal; and from the remains of leaves and branches, together with bones, not to mention other evidence, there is no doubt that much of what is now open down and bare hill was formerly covered with forest. There was therefore appropriate habitat for them all; and their needs, whether in water or on the trees, would be met by the former conditions of the country. It seems highly probable that the physical changes of the interior have been the chief cause of the extinction of so many living creatures, although the advent of man upon the scene may have hastened the process.[23]

As this chapter necessarily touches less on popular and more on scientific matters than the rest of this book, a few more words may be added on the palæontology and geology of Madagascar. Besides those extinct creatures already spoken of, remains of gigantic tortoises have been discovered; also species of swine and river-hog; an ox differing from the existing cattle of the country, and a large rail and a goose exceeding in size any living species. All these belonged to the Quaternary and Recent geological epochs. But far back in the period of the Secondary rocks a species of sloth lived in the forests, old forms of crocodile lived in the rivers; and there were three at least of those gigantic lizards which were the largest of all known land animals, and were the master existences of the Jurassic period.

To sum up in a sentence or two the salient features of Madagascar geology, it may be said that the whole eastern part of the island from north to south, comprising probably about three-fifths of the entire area, is composed of crystalline rocks—gneiss, granite, mica-schist, etc. But the western two-fifths of its surface consists chiefly of Secondary strata, including chalk and sandstones and limestones of the Jurassic and Cretaceous, periods, as well as a smaller area of rocks of the Eocene and Oligocene eras. A fringe of Quaternary deposits is also found along a great part of the west coast. It is evident, therefore, that the western side of the island has been repeatedly under the sea during the geological periods just mentioned, leaving the upper highland of ancient rocks as an island not half the extent of the present Madagascar. It has quite recently been found that a narrow edging of chalk rock extends for about one hundred and twenty miles on the central part of the east coast.[24] Plutonic rocks are found in several places in both the great geological divisions of the island, and also many outflows of volcanic rocks, of a much more recent date.

We have already spoken of the two principal groups of extinct craters which exist in the central portion of Madagascar. In the more southerly of these groups, Dr Mullens speaks of an ascent of Ivòko, one of the finest old volcanoes, which is eleven hundred and thirty feet high. This, he says, “was a vast crater, a quarter of a mile across; the encircling wall was complete except at the south, where the opening was fifty feet wide. Beneath us, half-a-mile to the east, was another crater, Iatsìfitra, second only to Ivòko, with its opening to the north. On the north-west shoulder of Ivòko were two other large craters, overhanging the village of Bétàfo, two more were close by to the north-east, and others were conspicuous ten miles to the north. On the south again were several others, the horseshoe shape being very marked in them all. Descending to the crater of Iatsìfitra, we observed that the lava rocks which had issued from it were black, sharp and fresh, as if they had been broken yesterday. On the plain I counted thirty greater piles of lava, like ruined fortresses, and numberless smaller ones. It was clear that like the Phlegræan fields in Italy, the entire plain had at some time been on fire; and that a hundred jets of flame and molten lava had spurted from its surface, hurling their blazing rockets into the sky. Altogether, in our journey to the west and south-west of the capital, we counted a hundred extinct craters, extending over an arc of ninety miles.”

Madagascar appears, therefore, to be the extinct central portion of a volcanic belt which extends from Great Comoro to the north-west, through the other islands of the group, Nòsibé and northern and central Madagascar, to Réunion to the east, a distance of thirteen hundred and sixty miles. And it is noteworthy that at each extremity of this belt there is a still active volcano—viz. Piton de Fournaise, in Réunion, and one eighty-five hundred feet high in Great Comoro.

As a country showing numerous traces of volcanic disturbance, Madagascar is almost every year visited by shocks of earthquake. Happily these are not of a severe character, and little damage is usually done; although often a strange subterranean roar accompanies them and a tremor of several seconds’ duration. The Malagasy still remember a rather severe earthquake which happened many years ago and detached a large mass of rock from the cliffs on the precipitous west side of the ridge on which Antanànarìvo is built. In September 1879 a severe shock, felt most in the Vònizòngo district, was experienced, and lasted for at least thirty seconds; this was accompanied by a loud rumbling sound, as of violent thunder, and in places the ground was split up by the shaking. In the year 1897, again, slight shocks were very numerous, and on some days and nights the earth appeared to have been in a constant state of tremor. These earth movements were felt more especially in the region of old volcanic disturbance about Lake Itàsy, where hundreds of slight shocks were experienced during seven or eight months. On the night of 2nd November four or five sharp movements occurred, one of which was more violent than anything remembered by the Malagasy, and wakened the whole population of the capital and around it in alarm. Chimney-stacks were thrown down, walls were cracked and ceilings damaged. This earthquake appears to have been felt over a very wide extent of country, from Tamatave and the east coast to Mèvatanàna away north-west, and as far as the Bétsiléo province in the south. It had the effect of stopping temporarily the mineral spring at Antsìrabé, which is so exactly like Vichy water; although, curiously enough, the hot-water springs, within a few yards of the other, were not affected. In the Ifànja marsh, a few miles from Itàsy, a small mud geyser is said to have appeared.

I will conclude this chapter, in which much has been said of extinct forms of existence, by a glimpse at the ancient animal life of the island. Let us try to sum up these in a few sentences.

It seems probable that Madagascar, when the first representatives of mankind occupied it, was a country much more fully covered by lakes and marshes, and also by forest, than it is at present. In these waters, amid vast cane-brakes and swamps of papyrus and sedge, wallowed and snorted herds of hippopotami; huge tortoises crawled over the low lands on their margins; tall ostrich-like birds, some over ten feet high, and others no larger than bustards, stalked over the marshy valleys; great rails hooted and croaked among the reeds, and clouds of large geese and other water-fowl flew screaming over the lakes; on the sand-banks crocodiles lay by scores basking in the sun; great ape-like lemurs climbed the trees and caught the birds; troops of river-hogs swam the streams and dug up roots among the woods; and herds of slender-legged zebu-oxen grazed on the open downs. These were the animals which the first wild men hunted with their palm-bark spears, and shot with their arrows tipped with burnt clay or stone.[25]

And as we look further back through long-past geological ages, when the clays and sandstones of the oolite, and the white masses of the chalk were being deposited in the coral-studded tropic seas and archipelagoes of Europe and other parts of the world, and when Madagascar was probably no island, but a peninsula of Eastern Africa, the mist opens for a moment, and we see vast reptile forms dimly through the haze; great slender-snouted gavials in the streams and lakes, sloths moving slowly along the branches of the trees, and huge dinosaurs, sixty to eighty feet long, crawling over the wooded plains, and tearing down whole trees with their powerful arms.

Such are some glimpses of the Madagascar of the past which the study of its rocks and fossils already opens to the mental eye. We may confidently look for further light upon the dim and distant bygone ages as we learn more of the geology of the country. The thick curtain which at present shrouds the old-world times will be yet more fully lifted, and we shall probably, ere many more years have passed, be able to draw many more mental pictures of the extinct animal life of the great African island.