Opposite the farm of Bermudez, two spacious caverns open into the crevice of Cuchivano, whence at times there issue flames, which may be seen at a great distance in the night; and, judging by the elevation of the rocks, above which these fiery exhalations ascend, we should be led to think that they rise several hundred feet. This phenomenon was accompanied by a subterranean, dull, and long continued noise, at the time of the last great earthquake of Cumana. It is observed chiefly during the rainy season; and the owners of the farms opposite the mountain of Cuchivano allege that the flames have become more frequent since December 1797.
In a herborizing excursion we made at Rinconada we attempted to penetrate into the crevice, wishing to examine the rocks which seemed to contain in their bosom the cause of these extraordinary conflagrations; but the strength of the vegetation, the interweaving of the lianas, and thorny plants, hindered our progress. Happily the inhabitants of the valley themselves felt a warm interest in our researches, less from the fear of a volcanic explosion, than because their minds were impressed with the idea that the Risco del Cuchivano contained a gold mine; and although we expressed our doubts of the existence of gold in a secondary limestone, they insisted on knowing "what the German miner thought of the richness of the vein." Ever since the time of Charles V and the government of the Welsers, the Alfingers, and the Sailers, at Coro and Caracas, the people of Terra Firma have entertained a great confidence in the Germans with respect to all that relates to the working of mines. Wherever I went in South America, when the place of my birth was known, I was shown samples of ore. In these colonies every Frenchman is supposed to be a physician, and every German a miner.
The farmers, with the aid of their slaves, opened a path across the woods to the first fall of the Rio Juagua; and on the 10th of September we made our excursion to the Cuchivano. On entering the crevice we recognised the proximity of tigers by a porcupine recently emboweled. For greater security the Indians returned to the farm, and brought back some dogs of a very small breed. We were assured that in the event of our meeting a jaguar in a narrow path he would spring on the dog rather than on a man. We did not proceed along the brink of the torrent, but on the slope of the rocks which overhung the water. We walked on the side of a precipice from two to three hundred feet deep, on a kind of very narrow cornice, like the road which leads from the Grindelwald along the Mettenberg to the great glacier. When the cornice was so narrow that we could find no place for our feet, we descended into the torrent, crossed it by fording, and then climbed the opposite wall. These descents are very fatiguing, and it is not safe to trust to the lianas, which hang like great cords from the tops of the trees. The creeping and parasite plants cling but feebly to the branches which they embrace; the united weight of their stalks is considerable, and you run the risk of pulling down a whole mass of verdure, if, in walking on a sloping ground, you support your weight by the lianas. The farther we advanced the thicker the vegetation became. In several places the roots of the trees had burst the calcareous rock, by inserting themselves into the clefts that separate the beds. We had some trouble to carry the plants which we gathered at every step. The cannas, the heliconias with fine purple flowers, the costuses, and other plants of the amomum family, here attain eight or ten feet in height, and their fresh tender verdure, their silky gloss, and the extraordinary development of the parenchyma, form a striking contrast with the brown colour of the arborescent ferns, the foliage of which is delicately shaped. The Indians made incisions with their large knives in the trunks of the trees, and fixed our attention on those beautiful red and gold-coloured woods, which will one day be sought for by our turners and cabinet-makers. They showed us a plant of the compositae order, twenty feet high (the Eupatorium laevigatum of Lamarck), the rose of Belveria,* (* Brownea racemosa.) celebrated for the brilliancy of its purple flowers, and the dragon's-blood of this country, which is a kind of croton not yet described.* (* Plants of families entirely different are called in the Spanish colonies of both continents, sangre de draco; they are dracaenas, pterocarpi, and crotons. Father Caulin Descrip. Corografica page 25, in speaking of resins found in the forests of Cumana, makes a just distinction between the Draco de la Sierra de Unare, which has pinnate leaves (Pterocarpus Draco), and the Draco de la Sierra de Paria, with entire and hairy leaves. The latter is the Croton sanguifluum of Cumanacoa, Caripe, and Cariaco. ) The red and astringent juice of this plant is employed to strengthen the gums. The Indians recognize the species by the smell, and more particularly by chewing the woody fibres. Two natives, to whom the same wood was given to chew, pronounced without hesitation the same name. We could avail ourselves but little of the sagacity of our guides, for how could we procure leaves, flowers, and fruits growing on trunks, the branches of which commence at fifty or sixty feet high? We were struck at finding in this hollow the bark of trees, and even the soil, covered with moss* and lichens. (* Real musci frondosi. We also found, besides a small Boletus stipitatus, of a snow-white colour, the Boletus igniarius, and the Lycoperdon stellatum of Europe. I had found this last only in very dry places in Germany and Poland.) The cryptogamous plants are here as common as in northern countries. Their growth is favoured by the moisture of the air, and the absence of the direct rays of the sun. Nevertheless the temperature is generally at 25 degrees in the day, and 19 degrees at night.
The rocks which bound the crevice of Cuchivano are perpendicular like walls, and are of the same calcareous formation which we observed the whole way from Punta Delgada. It is here a blackish grey, of compact fracture, tending sometimes towards the sandy fracture, and crossed by small veins of white carbonated lime. In these characteristic marks we thought we discovered the alpine limestone of Switzerland and the Tyrol, of which the colour is always deep, though in a less degree than that of the transition limestone.* (* Escher, in the Alpina volume 4 page 340.) The first of these formations constitutes the Cuchivano, the nucleus of the Imposible, and in general the whole group of the mountains of New Andalusia. I saw no petrifactions in it; but the inhabitants assert that considerable masses of shells are found at great heights. The same phenomenon occurs in the country about Salzburg.* (* In Switzerland, the solitary beds of shells, at the height of from 1300 to 2000 toises (in the Jungfrauhorn, the Dent de Morcle, and the Dent du Midi), belong to transition limestone.) At the Cuchivano the alpine limestone contains beds of marly clay,* (*Mergelschiefer.) three or four toises thick; and this geological fact proves on the one hand the identity of the alpenkalkstein with the zechstein of Thuringia, and on the other the affinity of formation existing between the alpine limestone and that of the Jura.* (* The Jura and the Alpine limestone are kindred formations, and they are sometimes difficult to be distinguished, where they lie immediately one upon another, as in the Apennines. The alpine limestone and the zechstein, famous among the geologists of Freyberg, are identical formations. This identity, which I noticed in the year 1793 (Uber die Grubenwetter), is a geological fact the more interesting, as it seems to unite the northern European formations to those of the central chain. It is known that the zechstein is situated between the muriatiferous gypsum and the conglomerate (ancient sandstone); or where there is no muriatiferous gypsum, between the slaty sandstone with roestones (buntesandstein, Wern.), and the conglomerate or ancient sandstone. It contains strata of schistous and coppery marl (bituminoce mergel and kupferschiefer) which form an important object in the working of mines at Mansfeld in Saxony, near Riegelsdorf in Hesse, and at Hasel and Prausnitz, in Silesia. In the southern part of Bavaria (Oberbaiern), I saw the alpine limestone, containing these same strata of schistous clay and marl, which, though thinner, whiter, and especially more frequent, characterize the limestone of Jura. Respecting the slates of Blattenberg, in the canton of Glaris which some mineralogists, because of their numerous impressions of fish, have long mistaken for the cupreous slates of Mansfeld, they belong, according to M. von Buch, to a real transition formation. All these geological data tend to prove that strata of marl, more or less mixed with carbon, are to be found in the limestone of Jura, in the alpine limestone, and in the transition schists. The mixture of carbon, sulphuretted iron, and copper, appears to me to augment with the relative antiquity of the formations.) The strata of marl effervesce with acids, though silex and alumina predominate in them: they are strongly impregnated with carbon, and sometimes blacken the hands, like a real vitriolic schistus. The supposed gold mine of Cuchivano, which was the object of our examination, is nothing but an excavation cut into one of those black strata of marl, which contain pyrites in abundance. The excavation is on the right bank of the river Juagua, and must be approached with caution, because the torrent there is more than eight feet deep. The sulphurous pyrites are found, some massive, and others crystallized and disseminated in the rock; their colour, of a very clear golden yellow, does not indicate that they contain copper. They are mixed with fibrous sulphuret of iron,* (* Haarkies.) and nodules of swinestone, or fetid carbonate of lime. The marly stratum crosses the torrent; and, as the water washes out metallic grains, the people imagine, on account of the brilliancy of the pyrites, that the torrent bears down gold. It is reported that, after the great earthquake which took place in 1766, the waters of the Juagua were so charged with gold that "men who came from a great distance, and whose country was unknown," established washing-places on the spot. They disappeared during the night, after having collected a great quantity of gold. It would be needless to show that this is a fable. Pyrites dispersed in quartzose veins, crossing the mica-slate, are often auriferous, no doubt; but no analogous fact leads to the supposition that the sulphuretted iron which is found in the schistose marls of the alpine limestone, contains gold. Some direct experiments, made with acids, during my abode at Caracas, showed that the pyrites of Cuchivano are not auriferous. Our guides were amazed at my incredulity. In vain I repeated that alum and sulphate of iron only could be obtained from this supposed gold mine; they continued picking up secretly every bit of pyrites they saw sparkling in the water. In countries possessing few mines, the inhabitants entertain exaggerated ideas respecting the facility with which riches are drawn from the bowels of the earth. How much time did we not lose during five years' travels, in visiting, on the pressing invitations of our hosts, ravines, of which the pyritous strata have borne for ages the imposing names of 'Minas de oro!' How often have we been grieved to see men of all classes, magistrates, pastors of villages, grave missionaries, grinding, with inexhaustible patience, amphibole, or yellow mica, in the hope of extracting gold from it by means of mercury! This rage for the search of mines strikes us the more in a climate where the ground needs only to be slightly raked to produce abundant harvests.
After visiting the pyritous marls of the Rio Juagua, we continued following the course of the crevice, which stretches along like a narrow canal overshadowed by very lofty trees. We observed strata on the left bank, opposite Cerro del Cuchivano, singularly crooked and twisted. This phenomenon I had often admired at the Ochsenberg, * in passing the lake of Lucerne. (* This mountain of Switzerland is composed of transition limestone. We find these same inflexions in the strata near Bonneville, at Nante d'Arpenas in Savoy, and in the valley of Estaubee in the Pyrenees. Another transition rock, the grauwakke of the Germans (very near the English killas), exhibits the same phenomenon in Scotland.) The calcareous beds of the Cuchivano and the neighbouring mountains keep pretty regularly the direction of north-north-east and south-south-west. Their inclination is sometimes north and sometimes south; most commonly they seem to take a direction towards the valley of Cumanacoa; and it cannot be doubted that the valley has an influence* on the inclination of the strata. (* The same observation may apply to the lake of Gemunden in Styria, which I visited with M. von Buch, and which is one of the most picturesque situations in Europe.)
We had suffered great fatigue, and were quite drenched by frequently crossing the torrent, when we reached the caverns of the Cuchivano. A wall of rock there rises perpendicularly to the height of eight hundred toises. It is seldom that in a zone where the force of vegetation everywhere conceals the soil and the rocks, we behold a great mountain presenting naked strata in a perpendicular section. In the middle of this section, and in a position unfortunately inaccessible to man, two caverns open in the form of crevices. We were assured that they are inhabited by nocturnal birds, the same as those we were soon to become acquainted with in the Cueva del Guacharo of Caripe. Near these caverns we saw strata of schistose marl, and found, with great astonishment, rock-crystals encased in beds of alpine limestone. They were hexahedral prisms, terminated with pyramids, fourteen lines long and eight thick. The crystals, perfectly transparent, were solitary, and often three or four toises distant from each other. They were enclosed in the calcareous mass, as the quartz crystals of Burgtonna,* (* In the duchy of Gotha.) and the boracite of Lunebourg, are contained in gypsum. There was no crevice near, or any vestige of calcareous spar.* (* This phenomenon reminds us of another equally rare, the quartz crystals found by M. Freiesleben in Saxony, near Burgorner, in the county of Mansfeld, in the middle of a rock of porous limestone (rauchwakke), lying immediately on the alpine limestone. The rock crystals, which are pretty common in the primitive limestone of Carrara, line the insides of cavities in the rocks, without being enveloped by the rock itself.)
We reposed at the foot of the cavern whence those flames were seen to issue, which of late years have become more frequent. Our guides and the farmer, an intelligent man, equally acquainted with the localities of the province, discussed, in the manner of the Creoles, the dangers to which the town of Cumanacoa would be exposed if the Cuchivano became an active volcano, or, as they expressed it, "se veniesse a reventar." It appeared to them evident, that since the great earthquakes of Quito and Cumana in 1797, New Andalusia was every day more and more undermined by subterranean fires. They cited the flames which had been seen to issue from the earth at Cumana; and the shocks felt in places where heretofore the ground had never been shaken. They recollected that at Macarapan, sulphurous emanations had been frequently perceived for some months past. We were struck with these facts, upon which were founded predictions that have since been almost all realized. Enormous convulsions of the earth took place at Caracas in 1812, and proved how tumultuously nature is agitated in the north-east part of Terra Firma.
But what is the cause of the luminous phenomena which are observed in the Cuchivano? The column of air which rises from the mouth of a burning volcano* is sometimes observed to shine with a splendid light. (* We must not confound this very rare phenomenon with the glimmering commonly observed a few toises above the brink of a crater, and which (as I remarked at Mount Vesuvius in 1805) is only the reflection of great masses of inflamed scoria, thrown up without sufficient force to pass the mouth of the volcano.) This light, which is believed to be owing to the hydrogen gas, was observed from Chillo, on the summit of the Cotopaxi, at a time when the mountain seemed in the greatest repose. According to the statements of the ancients, the Mons Albanus, near Rome, known at present under the name of Monte Cavo, appeared at times on fire during the night; but the Mons Albanus is a volcano recently extinguished, which, in the time of Cato, threw out rapilli;* (* "Albano monte biduum continenter lapidibus pluit."—Livy lib. 25 cap. 7. (Heyne, Opuscula Acad. tome 3 page 261.)) while the Cuchivano is a calcareous mountain, remote from any trap formation. Can these flames be attributed to the decomposition of water, entering into contact with the pyrites dispersed through the schistose marl? or is it inflamed hydrogen that issues from the cavern of Cuchivano? The marls, as the smell indicates, are pyritous and bituminous at the same time; and the petroleum springs at the Buen Pastor, and in the island of Trinidad, proceed probably from these same beds of alpine limestone. It would be easy to suppose some connexion between the waters filtering through this calcareous stone, and decomposed by pyrites and the earthquakes of Cumana, the springs of sulphuretted hydrogen in New Barcelona, the beds of native sulphur at Carupano, and the emanations of sulphurous acid which are perceived at times in the savannahs. It cannot be doubted also, that the decomposition of water by the pyrites at an elevated temperature, favoured by the affinity of oxidated iron for earthy substances, may have caused that disengagement of hydrogen gas, to the action of which several modern geologists have attributed so much importance. But in general, sulphurous acid is perceived more commonly than hydrogen in the eruption of volcanoes, and the odour of that acid principally prevails while the earth is agitated by violent shocks. When we take a general view of the phenomena of volcanoes and earthquakes, when we recollect the enormous distance at which the commotion is propagated below the basin of the sea, we readily discard explanations founded on small strata of pyrites and bituminous marls. I am of opinion that the shocks so frequently felt in the province of Cumana are as little to be attributed to the rocks above the surface of the earth, as those which agitate the Apennines are assignable to asphaltic veins or springs of burning petroleum. The whole of these phenomena depend on more general, I would almost say on deeper, causes; and it is not in the secondary strata which form the exterior crust of our globe, but in the primitive rocks, at an enormous distance from the soil, that we should seek the focus of volcanic action. The greater progress we make in geology, the more we feel the insufficiency of theories founded on observations merely local.
On the 12th of September we continued our journey to the convent of Caripe, the principal settlement of the Chayma missions. We chose, instead of the direct road, that by the mountains of the Cocollar* (* Is this name of Indian origin? At Cumana I heard it derived in a manner somewhat far-fetched from the Spanish word cogollo, signifying the heart of oleraceous plants. The Cocollar forms the centre of the whole group of the mountains of New Andalusia.) and the Turimiquiri, the height of which little exceeds that of Jura. The road first runs eastward, crossing over the length of three leagues the table-land of Cumanacoa, in a soil formerly levelled by the waters: it then turns to the south. We passed the little Indian village of Aricagua surrounded by woody hills. Thence we began to ascend, and the ascent lasted more than four hours. We crossed two-and-twenty times the river of Pututucuar, a rapid torrent, full of blocks of calcareous rock. When, on the Cuesta del Cocollar, we reached an elevation two thousand feet above the level of the sea, we were surprised to find scarcely any forests or great trees. We passed over an immense plain covered with gramineous plants. Mimosas with hemispheric tops, and stems only four or five feet high, alone vary the dull uniformity of the savannahs. Their branches are bent towards the ground or spread out like umbrellas. Wherever there are deep declivities, or masses of rocks half covered with mould, the clusia or cupey, with great nymphaea flowers, displays its beautiful verdure. The roots of this tree are eight inches in diameter, and they sometimes shoot out from the trunk at the height of fifteen feet above the soil.
After having climbed the mountain for a considerable time, we reached a small plain at the Hato del Cocollar. This is a solitary farm, situated on a table-land 408 toises high. We rested three days in this retreat, where we were treated with great kindness by the proprietor, Don Mathias Yturburi, a native of Biscay, who had accompanied us from the port of Cumana. We there found milk, excellent meat from the richness of the pasture, and above all, a delightful climate. During the day the centigrade thermometer did not rise above 22 or 23 degrees; a little before sunset it fell to 19, and at night it scarcely kept up to 14 degrees.* (* 11.2 degrees Reaum.) The nightly temperature was consequently seven degrees colder than that of the coasts, which is a fresh proof of an extremely rapid decrement of heat, the table-land of Cocollar being less elevated than the site of the town of Caracas.