Volume I Part 14 (2/2)

But this luxury of vegetation embellishes not only the external arch, it appears even in the vestibule of the grotto. We saw with astonishment plantain-leaved heliconias eighteen feet high, the praga palm-tree, and arborescent arums, following the course of the river, even to those subterranean places. The vegetation continues in the cave of Caripe as in those deep crevices of the Andes, half-excluded from the light of day, and does not disappear till, penetrating into the interior, we advance thirty or forty paces from the entrance. We measured the way by means of a cord; and we went on about four hundred and thirty feet without being obliged to light our torches. Daylight penetrates far into this region, because the grotto forms but one single channel, keeping the same direction, from south-east to north-west. Where the light began to fail, we heard from afar the hoa.r.s.e sounds of the nocturnal birds; sounds which the natives think belong exclusively to those subterraneous places.

The guacharo is of the size of our fowls. It has the mouth of the goat-suckers and procnias, and the port of those vultures whose crooked beaks are surrounded with stiff silky hairs. Suppressing, with M. Cuvier, the order of picae, we must refer this extraordinary bird to the pa.s.seres, the genera of which are connected with each other by almost imperceptible transitions. It forms a new genus, very different from the goatsucker, in the loudness of its voice, in the vast strength of its beak (containing a double tooth), and in its feet without the membranes which unite the anterior phalanges of the claws. It is the first example of a nocturnal bird among the Pa.s.seres dentirostrati. Its habits present a.n.a.logies both with those of the goatsuckers and of the alpine crow.* (* Corvus Pyrrhocorax.) The plumage of the guacharo is of a dark bluish grey, mixed with small streaks and specks of black.

Large white spots of the form of a heart, and bordered with black, mark the head, wings, and tail. The eyes of the bird, which are dazzled by the light of day, are blue, and smaller than those of the goatsucker. The spread of the wings, which are composed of seventeen or eighteen quill feathers, is three feet and a half. The guacharo quits the cavern at nightfall, especially when the moon s.h.i.+nes. It is almost the only frugiferous nocturnal bird yet known; the conformation of its feet sufficiently shows that it does not hunt like our owls. It feeds on very hard fruits, like the nutcracker* (* Corvus caryocatactes, C. glandarius. Our Alpine crow builds its nest near the top of Mount Liba.n.u.s, in subterranean caverns, nearly like the guacharo. It also has the horribly shrill cry of the latter.) and the pyrrhocorax. The latter nestles also in clefts of rocks, and is known by the name of the night-crow. The Indians a.s.sured us that the guacharo does not pursue either the lamellicornous insects or those phalaenae which serve as food to the goatsuckers. A comparison of the beaks of the guacharo and the goatsucker serves to denote how much their habits must differ. It would be difficult to form an idea of the horrible noise occasioned by thousands of these birds in the dark part of the cavern. Their shrill and piercing cries strike upon the vaults of the rocks, and are repeated by the subterranean echoes. The Indians showed us the nests of the guacharos by fixing a torch to the end of a long pole.

These nests were fifty or sixty feet high above our heads, in holes in the shape of funnels, with which the roof of the grotto is pierced like a sieve. The noise increased as we advanced, and the birds were scared by the light of the torches of copal. When this noise ceased a few minutes around us, we heard at a distance the plaintive cries of the birds roosting in other ramifications of the cavern. It seemed as if different groups answered each other alternately.

The Indians enter the Cueva del Guacharo once a year, near midsummer. They go armed with poles, with which they destroy the greater part of the nests. At that season several thousand birds are killed; and the old ones, as if to defend their brood, hover over the heads of the Indians, uttering terrible cries. The young,*

(* Called Los pollos del Guacharo.) which fall to the ground, are opened on the spot. Their peritoneum is found extremely loaded with fat, and a layer of fat reaches from the abdomen to the a.n.u.s, forming a kind of cus.h.i.+on between the legs of the bird. This quant.i.ty of fat in frugivorous animals, not exposed to the light, and exerting very little muscular motion, reminds us of what has been observed in the fattening of geese and oxen. It is well known how greatly darkness and repose favour this process. The nocturnal birds of Europe are lean, because, instead of feeding on fruits, like the guacharo, they live on the scanty produce of their prey.

At the period commonly called, at Caripe, the oil harvest,* (* La cosecha de la manteca.) the Indians build huts with palm-leaves, near the entrance, and even in the porch of the cavern. There, with a fire of brushwood, they melt in pots of clay the fat of the young birds just killed. This fat is known by the name of b.u.t.ter or oil (manteca, or aceite) of the guacharo. It is half liquid, transparent, without smell, and so pure that it may be kept above a year without becoming rancid. At the convent of Caripe no other oil is used in the kitchen of the monks but that of the cavern; and we never observed that it gave the aliments a disagreeable taste or smell.

The race of the guacharos would have been long ago extinct, had not several circ.u.mstances contributed to its preservation. The natives, restrained by their superst.i.tious ideas, seldom have courage to penetrate far into the grotto. It appears also, that birds of the same species dwell in neighbouring caverns, which are too narrow to be accessible to man. Perhaps the great cavern is repeopled by colonies which forsake the small grottoes; for the missionaries a.s.sured us that hitherto no sensible diminution of the birds has been observed. Young guacharos have been sent to the port of c.u.mana, and have lived there several days without taking any nourishment, the seeds offered to them not suiting their taste.

When the crops and gizzards of the young birds are opened in the cavern, they are found to contain all sorts of hard and dry fruits, which furnish, under the singular name of guacharo seed (semilla del guacharo), a very celebrated remedy against intermittent fevers. The old birds carry these seeds to their young. They are carefully collected, and sent to the sick at Cariaco, and other places of the low regions, where fevers are generally prevalent.

As we continued to advance into the cavern, we followed the banks of the small river which issues from it, and is from twenty-eight to thirty feet wide. We walked on the banks, as far as the hills formed of calcareous incrustations permitted us. Where the torrent winds among very high ma.s.ses of stalact.i.tes, we were often obliged to descend into its bed, which is only two feet deep. We learned with surprise, that this subterranean rivulet is the origin of the river Caripe, which, at the distance of a few leagues, where it joins the small river of Santa Maria, is navigable for canoes. It flows into the river Areo under the name of Cano do Terezen. We found on the banks of the subterranean rivulet a great quant.i.ty of palm-tree wood, the remains of trunks, on which the Indians climb to reach the nests hanging from the roofs of the cavern. The rings, formed by the vestiges of the old footstalks of the leaves, furnish as it were the steps of a ladder perpendicularly placed.

The Grotto of Caripe preserves the same direction, the same breadth, and its primitive height of sixty or seventy feet, to the distance of 472 metres, or 1458 feet, accurately measured. We had great difficulty in persuading the Indians to pa.s.s beyond the anterior portion of the grotto, the only part which they annually visit to collect the fat. The whole authority of 'los padres' was necessary to induce them to advance as far as the spot where the soil rises abruptly at an inclination of sixty degrees, and where the torrent forms a small subterranean cascade.* (* We find the phenomenon of a subterranean cascade, but on a much larger scale, in England, at Yordas Cave, near Kingsdale in Yorks.h.i.+re.) The natives connect mystic ideas with this cave, inhabited by nocturnal birds; they believe that the souls of their ancestors sojourn in the deep recesses of the cavern. ”Man,” say they, ”should avoid places which are enlightened neither by the sun (zis), nor by the moon (nuna).” 'To go and join the guacharos,' is with them a phrase signifying to rejoin their fathers, to die. The magicians (piaches) and the poisoners (imorons) perform their nocturnal tricks at the entrance of the cavern, to conjure the chief of the evil spirits (ivorokiamo). Thus in every region of the earth a resemblance may be traced in the early fictions of nations, those especially which relate to two principles governing the world, the abode of souls after death, the happiness of the virtuous and the punishment of the guilty. The most different and most barbarous languages present a certain number of images, which are the same, because they have their source in the nature of our intelligence and our sensations.

Darkness is everywhere connected with the idea of death. The Grotto of Caripe is the Tartarus of the Greeks; and the guacharos, which hover over the rivulet, uttering plaintive cries, remind us of the Stygian birds.

At the point where the river forms the subterranean cascade, a hill covered with vegetation, which is opposite to the opening of the grotto, presents a very picturesque aspect. It is seen at the extremity of a straight pa.s.sage, 240 toises in length. The stalact.i.tes descending from the roof, and resembling columns suspended in the air, are relieved on a back-ground of verdure. The opening of the cavern appeared singularly contracted, when we saw it about the middle of the day, illumined by the vivid light reflected at once from the sky, the plants, and the rocks. The distant light of day formed a strange contrast with the darkness which surrounded us in the vast cavern. We discharged our guns at a venture, wherever the cries of the nocturnal birds and the flapping of their wings, led us to suspect that a great number of nests were crowded together. After several fruitless attempts M. Bonpland succeeded in killing a couple of guacharos, which, dazzled by the light of the torches, seemed to pursue us. This circ.u.mstance afforded me the means of making a drawing of this bird, which had previously been unknown to naturalists. We climbed, not without difficulty, the small hill whence the subterranean rivulet descends. We saw that the grotto was perceptibly contracted, retaining only forty feet in height, and that it continued stretching to north-east, without deviating from its primitive direction, which is parallel to that of the great valley of Caripe.

In this part of the cavern, the rivulet deposits a blackish mould, very like the matter which, in the grotto of Muggendorf, in Franconia, is called ”the earth of sacrifice.”* (* Opfer-erde of the cavern of Hohle Berg (or Hole Mountain,--a mountain pierced entirely through.)) We could not discover whether this fine and spongy mould falls through the cracks which communicate with the surface of the ground above, or is washed down by the rain-water penetrating into the cavern. It was a mixture of silex, alumina, and vegetable detritus. We walked in thick mud to a spot where we beheld with astonishment the progress of subterranean vegetation.

The seeds which the birds carry into the grotto to feed their young, spring up wherever they fix in the mould which covers the calcareous incrustations. Blanched stalks, with some half-formed leaves, had risen to the height of two feet. It was impossible to ascertain the species of these plants, their form, colour, and aspect having been changed by the absence of light. These traces of organization amidst darkness forcibly excited the curiosity of the natives, who examined them with silent meditation inspired by a place they seemed to dread. They evidently regarded these subterranean plants, pale and deformed, as phantoms banished from the face of the earth. To me the scene recalled one of the happiest periods of my early youth, a long abode in the mines of Freyberg, where I made experiments on the effects of blanching (etiolement), which are very different, according as the air is pure or overcharged with hydrogen or azote.

The missionaries, with all their authority, could not prevail on the Indians to penetrate farther into the cavern. As the roof became lower the cries of the guacharos were more and more shrill.

We were obliged to yield to the pusillanimity of our guides, and trace back our steps. The appearance of the cavern was however very uniform. We found that a bishop of St. Thomas of Guiana had gone farther than ourselves. He had measured nearly 2500 feet from the mouth to the spot where he stopped, but the cavern extended still farther. The remembrance of this fact was preserved in the convent of Caripe, without the exact period being noted. The bishop had provided himself with great torches of white Castile wax. We had torches composed only of the bark of trees and native resin. The thick smoke which issued from these torches, in a narrow subterranean pa.s.sage, hurts the eyes and obstructs the respiration.

On turning back to go out of the cavern, we followed the course of the torrent. Before our eyes became dazzled with the light of day we saw on the outside of the grotto the water of the river sparkling amid the foliage of the trees which shaded it. It was like a picture placed in the distance, the mouth of the cavern serving as a frame. Having at length reached the entrance, we seated ourselves on the bank of the rivulet, to rest after our fatigues. We were glad to be beyond the hoa.r.s.e cries of the birds, and to leave a place where darkness does not offer even the charm of silence and tranquillity. We could scarcely persuade ourselves that the name of the Grotto of Caripe had hitherto been unknown in Europe;* for the guacharos alone might have sufficed to render it celebrated. (* It is surprising that Father Gili, author of the Saggio di Storia Americana, does not mention it, though he had in his possession a ma.n.u.script written in 1780 at the convent of Caripe. I gave the first information respecting the Cueva del Guacharo in 1800, in my letters to Messrs. Delambre and Delametherie, published in the Journal de Physique.) These nocturnal birds have been no where yet discovered, except in the mountains of Caripe and c.u.manacoa. The missionaries had prepared a repast at the entry of the cavern. Leaves of the banana and the vijao,* (* Heliconia bihai, Linn. The Creoles have changed the b of the Haitian word bihao into v, and the h into j, agreeably to the Castilian p.r.o.nunciation.) which have a silky l.u.s.tre, served us as a table-cloth, according to the custom of the country. Nothing was wanting to our enjoyment, not even remembrances, which are so rare in those countries, where generations disappear without leaving a trace of their existence.

Before we quit the subterranean rivulet and the nocturnal birds, let us cast a last glance at the cavern of the Guacharo, and the whole of the physical phenomena it presents. When we have step by step pursued a long series of observations modified by the localities of a place, we love to stop and raise our views to general considerations. Do the great cavities, which are exclusively called caverns, owe their origin to the same causes as those which have produced the lodes of veins and of metalliferous strata, or the extraordinary phenomenon of the porosity of rocks?

Do grottoes belong to every formation, or to that period only when organized beings began to people the surface of the globe? These geological questions can be solved only so far as they are directed by the actual state of things, that is, of facts susceptible of being verified by observation.

Considering rocks according to the succession of eras, we find that primitive formations exhibit very few caverns. The great cavities which are observed in the oldest granite, and which are called fours (ovens) in Switzerland and in the south of France, when they are lined with rock crystals, arise most frequently from the union of several contemporaneous veins of quartz,* (* Gleichzeitige Trummer. To these stone veins which appear to be of the same age as the rock, belong the veins of talc and asbestos in serpentine, and those of quartz traversing schist (Thonschiefer). Jameson on Contemporaneous Veins, in the Mem. of the Wernerian Soc.) of feldspar, or of fine-grained granite. The gneiss presents, though more seldom, the same phenomenon; and near Wunsiedel,* (* In Franconia, south-east of Luchsburg.) at the Fichtelgebirge, I had an opportunity of examining crystal fours of two or three feet diameter, in a part of the rock not traversed by veins. We are ignorant of the extent of the cavities which subterranean fires and volcanic agitations may have produced in the bowels of the earth in those primitive rocks, which, containing considerable quant.i.ties of amphibole, mica, garnet, magnetic iron-stone, and red schorl (t.i.tanite), appear to be anterior to granite. We find some fragments of these rocks among the matters ejected by volcanoes.

The cavities can be considered only as partial and local phenomena; and their existence is scarcely any contradiction to the notions we have acquired from the experiments of Maskelyne and Cavendish on the mean density of the earth.

In the primitive mountains open to our researches, real grottoes, those which have some extent, belong only to calcareous formations, such as the carbonate or sulphate of lime. The solubility of these substances appears to have favoured the action of the subterranean waters for ages. The primitive limestone presents s.p.a.cious caverns as well as transition limestone,* and that which is exclusively called secondary. (* In the primitive limestone are found the Kuetzel-loch, near Kaufungen in Silesia, and probably several caverns in the islands of the Archipelago. In the transition limestone we remark the caverns of Elbingerode, of Rubeland, and of Scharzfeld, in the Hartz; those of the Salzfluhe in the Grisons; and, according to Mr. Greenough, that of Torbay in Devons.h.i.+re.) If these caverns be less frequent in the first, it is because this stone forms in general only layers subordinate to the mica-slate,*

(* Sometimes to gneiss, as at the Simplon, between Dovredo and Crevola.) and not a particular system of mountains, into which the waters may filter, and circulate to great distances. The erosions occasioned by this element depend not only on its quant.i.ty, but also on the length of time during which it remains, the velocity it acquires by its fall, and the degree of solubility of the rock. I have observed in general, that the waters act more easily on the carbonates and the sulphates of lime of secondary mountains than on the transition limestones, which have a considerable mixture of silex and carbon. On examining the internal structure of the stalact.i.tes which line the walls of caverns, we find in them all the characters of a chemical precipitate.

As we approach those periods in which organic life develops itself in a greater number of forms, the phenomenon of grottoes becomes more frequent. There exist several under the name of baumen,* (* In the dialect of the German Swiss, Balmen. The Baumen of the Sentis, of the Mole, and of the Beatenberg, on the borders of the lake of Thun, belong to the Alpine limestone.) not in the ancient sandstone to which the great coal formation belongs, but in the Alpine limestone, and in the Jura limestone, which is often only the superior part of the Alpine formation. The Jura limestone* (* I may mention only the grottoes of Boudry, Motiers-Travers, and Valorbe, in the Jura; the grotto of Balme near Geneva; the caverns between Muggendorf and Gaylenreuth in Franconia; Sowia Jama, Ogrodzimiec, and Wlodowice, in Poland.) so abounds with caverns in both continents, that several geologists of the school of Freyberg have given it the name of cavern-limestone (hohlenkalkstein). It is this rock which so often interrupts the course of rivers, by engulfing them into its bosom. In this also is formed the famous Cueva del Guacharo, and the other grottoes of the valley of Caripe. The muriatiferous gypsum,* (* Gypsum of Bottendorf, schlottengyps.) whether it be found in layers in the Jura or Alpine limestone, or whether it separate these two formations, or lie between the Alpine limestone and argillaceous sandstone, also presents, on account of its great solubility, enormous cavities, sometimes communicating with each other at several leagues distance. After the limestone and gypseous formations, there would remain to be examined, among the secondary rocks, a third formation, that of the argillaceous sandstone, newer than the brine-spring formations; but this rock, composed of small grains of quartz cemented by clay, seldom contains caverns; and when it does, they are not extensive.

Progressively narrowing towards their extremity, their walls are covered with a brown ochre.

We have just seen, that the form of grottoes depends partly on the nature of the rocks in which they are found; but this form, modified by exterior agents, often varies even in the same formation. The configuration of caverns, like the outline of mountains, the sinuosity of valleys, and so many other phenomena, present at first sight only irregularity and confusion. The appearance of order is resumed, when we can extend our observations over a vast s.p.a.ce of ground, which has undergone violent, but periodical and uniform revolutions. From what I have seen in the mountains of Europe, and in the Cordilleras of America, caverns may be divided, according to their interior structure, into three cla.s.ses. Some have the form of large clefts or crevices, like veins not filled with ore; such as the cavern of Rosenmuller, in Franconia, Elden-hole, in the peak of Derbys.h.i.+re, and the Sumideros of Chamacasapa in Mexico. Other caverns are open to the light at both ends. These are rocks really pierced; natural galleries, which run through a solitary mountain: such are the Hohleberg of Muggendorf, and the famous cavern called Dantoe by the Ottomite Indians, and the Bridge of the Mother of G.o.d, by the Mexican Spaniards. It is difficult to decide respecting the origin of these channels, which sometimes serve as beds for subterranean rivers.

Are these pierced rocks hollowed out by the impulse of a current?

or should we rather admit that one of the openings of the cavern is owing to a falling down of the earth subsequent to its original formation; to a change in the external form of the mountain, for instance, to a new valley opened on its flank? A third form of caverns, and the most common of the whole, exhibits a succession of cavities, placed nearly on the same level, running in the same direction, and communicating with each other by pa.s.sages of greater or less breadth.

To these differences of general form are added other circ.u.mstances not less remarkable. It often happens, that grottoes of little s.p.a.ce have extremely wide openings; whilst we have to creep under very low vaults, in order to penetrate into the deepest and most s.p.a.cious caverns. The pa.s.sages which unite partial grottoes, are generally horizontal. I have seen some, however, which resemble funnels or wells, and which may be attributed to the escape of some elastic fluid through a ma.s.s before being hardened. When rivers issue from grottoes, they form only a single, horizontal, continuous channel, the dilatations of which are almost imperceptible; as in the Cueva del Guacharo we have just described, and the cavern of San Felipe, near Tehuilotepec in the western Cordilleras of Mexico. The sudden disappearance* of the river (* In the night of the 16th April, 1802.), which took its rise from this last cavern, has impoverished a district in which farmers and miners equally require water for refres.h.i.+ng the soil and for working hydraulic machinery.

Considering the variety of structure exhibited by grottoes in both hemispheres, we cannot but refer their formation to causes totally different. When we speak of the origin of caverns we must choose between two systems of natural philosophy: one of these systems attributes every thing to instantaneous and violent commotions (for example, to the elastic force of vapours, and to the heavings occasioned by volcanoes); while the other rests on the operation of small powers, which produce effects almost insensibly by progressive action. Those who love to indulge in geological hypotheses must not, however, forget the horizontality so often remarked amidst gypseous and calcareous mountains, in the position of grottoes communicating with each other by pa.s.sages. This almost perfect horizontality, this gentle and uniform slope, appears to be the result of a long abode of the waters, which enlarge by erosion clefts already existing, and carry off the softer parts the more easily, as clay or muriate of soda is found mixed with the gypsum and fetid limestone. These effects are the same, whether the caverns form one long and continued range, or several of these ranges lie one over another, as happens almost exclusively in gypseous mountains.

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