geological description of south america.

By the late f. a. von humboldt.

This valuable man intended to return to Europe by the way of the Manillas; but we learn, that, while he was waiting for a ſhip at Acapulco, he was ſeized with a fever, which carried him off in a few days.

His papers and journals are, however, on their way to Europe.

SINCE I lent to Madrid the two firſt ſketches of a geological delineation of South America, from the Caraccas and Nueva Valencia, I have travelled twelve hundred miles, and deſcribed a ſquare between Caribe, Portocabello, Pimichin, and Eſmeralda, a ſpace comprehending above 59,000 ſquare miles; for I am not acquainted with the land between the mountain Parea and Portocabello, and between the northern coaſt and the valley of the Black River.

In conſequence of the great circumference of this diſtrict, I muſt content myſelf with delineating it in a general manner, and, to avoid details, with deſcribing the conſtruction of the earth, the declivity of the land, the direction and inclination of the mountains, their relative ages, their ſimilarity with the formation of thoſe in Europe.

Theſe are the circumſtances moſt neceſſary to be known in this ſcience.

We muſt proceed in mineralogy as in geography; we are acquainted with ſtones, but not with mountains; we know the materials, but we are ignorant of the whole of which they form component parts.

I wiſh I may be able, amidſt the variety of the objects which occupy my attention during my travels, to throw any light on the ſtructure of the earth.

The laborious journeys which, for eight years, I have made through Europe had no other object; and if I have the good fortune to return to Europe, and to recover my geological manuſcripts which I left behind me in France and Germany, I ſhall venture to give a ſketch of the ſtructure of the earth.

What I have long ſaid, that the direction and inclination, the riſing and falling, of the primitive ſtrata, the angles which they form with the meridian of the place, and with the axis of the earth, are independent of the direction and depreſſion of the mountains; that they depend on laws, and that they obſerve a general paralleliſm which can be founded only in the motion and rotation of the earth; what Freieſleben, Von Buch, and Gruner, have proved better than I, will be found confirmed, namely, that the ſucceſſion of the alluvial ſtrata, which was conſidered as a peculiarity of certain provinces, ſuch as Thuringia and Derbyſhire, takes place generally; and that there appears an identity in the order of the ſtrata; from which there is reaſon to conclude that the ſame depoſition has been effected at the ſame time over the whole ſurface of the earth.

All theſe ideas are of the greateſt importance, not only to the philoſopher, who endeavours to elevate himſelf to general principles, but alſo to the miner, who muſt conceive in his mind what he has not before his eyes, and guide himſelf by analogy deduced from actual experience.

Before I deſcribe the ſituation of the mountains which I have obſerved from the coaſt to the province of Venezuela, I ſhall give a general view of the form of this continent.

Unfortunately there are no early obſervations to ſerve as a ground for this deſcription.

For half a century paſt many accidental obſervations reſpecting this land have been collected, but not a ſingle idea relating to its geology has been made known.

The great genius of Condamine, the zeal of Don George Juan de Ulloa, would certainly not have left us in the dark on this ſubject, had mineralogy been more cultivated at the time when they wrote.

All that could then be done was to meaſure and to take levels.

As they were employed on the high cordillera of the Andes, which extends north and ſouth from Zitara, as far as Cape Pilar, and beheld with wonder the immenſe height of the mountains, they forgot that South America exhibits other cordilleras, which extend eaſt and weſt parallel to the equator, and which, on account of their height, deſerve as much the attention of naturaliſts as the Carpathians, Caucaſus, the Alps of the Valais, and the Pyrenees.

The whole immenſe tract on the weſt ſide of the Andes, which extends obliquely to the coaſt of Guiana and Braſil, is deſcribed as a low plain, expoſed to the inundation of the rivers.

As only a few Franciſcan miſſionaries and a few ſoldiers have been able to penetrate over the cataracts to Rio Negro, the inhabitants of the coaſt of Caraccas imagine that the immenſe plains (the Llanos de Calabozo, del Guarico, and de Apure,) which they ſee to the ſouth, beyond the valleys of Aragua, extend without interruption to the Pampas of Buenos-Ayres, and to the country of the Patagonians; but the extent of theſe plains is far from being ſo great; they are not uninterrupted plains, they are rather phenomena of the ſame kind as thoſe preſented by Canada and Yucatan, the iſland of St. Domingo, the north of Sierra de S. Martha, the province of Barcelona, and the land between Monte-Video and Mendoza, New Holland, the eaſtern part of Hungary, and the country of Hanover.

They are ſeparated from each other by the cordilleras, and are as far from lying in the ſame plane as the deſarts of Africa, and the ſteppes of Tartary, which riſe by gradations, according to the diſtance from the ſea-coaſt.

When one conſiders the irruptions which the North Sea, the Mediterranean, &c. have made into the Old World, the direction of its cordilleras appears not to be very different from that of thoſe in the New World, as moſt naturaliſts have aſſerted.

We are acquainted alſo with the traces of ſeveral high chains of mountains which extend from north to ſouth, and run out from thoſe which extend eaſt and weſt.

The garnet and micaceous ſchiſtus of Norway, Scotland, Wales, Brittany, the province of Gallicia, Alemtego, Cape Bogador, (I have found the ſame with granite on Teneriff,) the upper part of Guinea, Congo, and the Table Mountain, as alſo the original mountains of Orenburg, Caucaſus, Lebanon, of Abyſſinia, and Madagaſcar, ſeem at firſt to have formed nothing elſe than two large cordilleras parallel to the meridian.

In the New World theſe cordilleras run parallel to the meridian from Cape Pilar to the north of California beyond Nootka and Prince William’s Sound towards the Aleganhey mountains, which were diſcovered in 1792 by Mr. Stewart, on his journey to the fources of the Miſſoury, the northern part of the Andes, which is inhabited by Indians nearly as much civilized as the Peruvians were fifteen hundred years ago.

From this cordillera proceed ramifications of the original mountains, which extend from weſt to eaſt.

With thoſe of North America I am not acquainted, but it appears that ſome exiſt in Canada under the latitude of 50°, and 42° north latitude, as in the deſtroyed continent of the Gulf of Mexico under 19° and 22°; as is proved by the mountains of Cuba and Saint Domingo.

In South America there are three chains of original mountains which run parallel to the equator: the chain of the coaſt under 9° and 10°; that chain which is in the great cataracts of Autures (in latitude 5° 39′) is between latitude 3° and 7°; and that in Maipure in 5° 12′ 50″, which I therefore call the chain of the cataracts or that of Parime, and the chain of Chequitos under 15° and 20° ſouth latitude.

Theſe chains in the old continent on this ſide of the Weſtern Ocean can be traced, and it is ſeen how the original mountains of Fernambouc, Minas, La Bahia, and Janeiro, correſpond, under the ſame latitude, to thoſe of Congo, as the immenſe plains near the river Amazon lie oppoſite to the plains of Lower Guinea, the cordillera of the cataracts oppoſite to thoſe of Upper Guinea, and the Llanos of the Miſſiſſippi, ſince the irruption of the Gulf of Mexico, a property of the ſea, oppoſite to the Deſart of Serah.

This view will appear to be leſs hazarded when one reflects in what manner the old continent has been ſeparated from the new one by the force of the water.

The form of the coaſts, and the ſalient and re-entering angles of America, Africa, and Europe, are a ſufficient proof of this cataſtrophe.

What we call the Atlantic Ocean is nothing elſe than a valley ſcooped out by the ſea.

The pyramidal form of all the continents, with their ſummits turned ſouthwards, the great flattening of the earth at the ſouth pole, and other phenomena, obſerved by Dr. Forſter, ſeem to ſhew that the influx of the water was from the ſouth.

On the coaſt of Braſil, from Rio Janeiro to Fernambouc, it found reſiſtance, and taking a direction from the latitude of 50° north towards the north eaſt, where it ſcooped out the Gulf of Guinea, near Loango Benin and Mine, it was obliged by the mountains of Upper Guinea to direct itſelf north-weſt, and ſeparated, to the latitude of 23° north, the coaſt of Guinea from Mexico and Florida.

The force of the waters was ſtill broken by the cordillera of the United States of America, and once more turned towards the northeaſt, and ſeems to have ſpared leſs the weſtern coaſt of Europe than the northern of America.

The leaſt breadth of this channel is at the Braſils and Greenland; but, agreeably to the geographical hiſtory of plants and animals, it ſeems to have been formed at a time when the organic creation had not been properly expanded.

It would be of great importance to geology if a ſea voyage were undertaken, at the expence of ſome government, to examine the riſing and depreſſion and the relative ſituation of the mountains to the ſalient and re-entering angles of America and Africa.

The ſame analogy would be found here as is obſerved in the Engliſh Channel, in the Sound, the Straits of Gibraltar, and the Helleſpont; ſmall creeks which are as new as the ſecondary formation of the chalk-rocks of Jura, of Pappenheim, La Mancha, Marſeilles, Derbyſhire, and Suez, which have all been produced at the ſame time by precipitation.

Of the three cordilleras of primitive mountains which traverſe South America from weſt to eaſt, the moſt northern, that of Venezuela, is the higheſt, but narroweſt.

The real chain of the Andes extends from the large plain of Quito, through Popayan and Choco, to the weſtern ſide of the river Atrato, (or Rio San Juan,) between the valley of Tatabé, in the provinces of Zitara and Biruguete, towards the iſthmus, where it forms a mountainous diſtrict of not more than two or three hundred toiſes in height on the bank of the Chagre.

From theſe Andes ariſes the cordillera on the coaſt of Venezuela.

Rows of mountains higher, but forming groups leſs regular, extend on the eaſt ſide of the Rio Atrato, under the name of the Sierra de Abibé and the Montes de Cauca, through the high ſavannahs of Jolu towards Magdalen River and the province of St. Martha.

The cordillera of the coaſt contracts itſelf like that of the Gulf of Mexico, approaches nearer to Cape Vela, and then proceeds firſt from ſouthſouth weſt to north north eaſt, and then from weſt to eaſt to the ridge of Paria, or rather to the Punta de la Galera in the Iſland of Trinidad.

Its greateſt height is found at that place where it has the name of Sierra de Nevada de St. Martha, in latitude 10° 2′, and of Sierra Nevada de Merida, in latitude 8° 30′; the former is about 5000, the latter 5400 Spaniſh ells, (varas) or 2350 toiſes in height.

The Paramo de la Roſa and de Macuchi, and alſo the mountain of Merida, are continually covered with ſnow: boiling water, with hydrogenated ſulphur, iſſnes from their ſides, and they exceed in height the Peak of Teneriff, and are, perhaps, equal to Mont Blanc, which has been more accurately meaſured.

Theſe coloſſal maſſes and St. Martha ſtand almoſt inſulated, being ſurrounded by few high ridges.— To the weſt of Santa Fé, or as far as the Sierra of Zuindiu, no ſnow-clad peaks are ſeen, and the Sierra Nevada de Merida ſtands at the edge of the plain of Caraccas, which is ſcarcely forty toiſes above the level of the ſea.

Mont Blanc, which terminates the high ridge of the Alps, exhibits the ſame phenomenon.

The altitude of the higheſt mountains, however, is ſo very ſmall in proportion to the magnitude of the earth, that it would appear that very ſmall local cauſes ought to have accumulated more matter in theſe points.

That part of the cordillera of the coaſt which lies to the weſt of Maratayabo- Sees, and joins the Andes, has large valleys extending from north to ſouth, ſuch as that of Magdalena, of Cauca, of Saint George, of Sinu, and Atrato.

They are very long and narrow, but covered with wood.

On the other hand, that part of the cordillera which extends from Merida to Trinidad incloſes three valleys, lying eaſt and weſt, which ſhew by certain ſigns, like Bohemia, or the Haſlithal of Swiſſerland, that they have formerly been lakes the water of which has evaporated or run off by opening for itſelf a paſſage.

Theſe three valleys are incloſed by the two parallel rows of mountains, into which the cordillera of the coaſt divides itſelf, from Cape Vela to Cape Codera; the northern row is a continuation of Saint Martha, the ſouthern a prolongation of Sierra Nevada de Merida.

The firſt extends through Burburuta, Rincon del Diablo; through the Sierras de Mariara, the mountain Aguaſnegras, Monte de Arila, and the Silla de Caracas, to Cape Codera.

The ſecond from three to four miles more to the ſouth, extends through Guigni, La Palma, the high ſummits of Guairaima, Tiara, Guiripa, and the Savana de Ocumare, as far as the mouths of the Tuy.

Theſe two chains unite with two arms, which run from north to ſouth, like, as it were, dykes, by which theſe old lakes were confined within their boundaries.

Theſe dykes are, on the weſt, the mountains of Carora, Tonto, Saint Maria, Saint Philips, and Aroa; they ſeparate the Llanos de Monai from the valleys of Aragua: on the eaſt they are the naked ſummits of Los Teques, Coquiza, Buena Viſta, and the Altos de S. Pedro, by which the valley of Aragua or the ſources of the Tuy (for there is only one valley between the bottom of Coquiza, or the Hacienda de Briſenno, to Valencia,) from the valley of Garaccas.

On the eaſt, from Cape Codera, the greater part of the cordillera of the coaſt of Venezuola was deſtroyed and laid under water by the great cataſtrophe which formed the Gulf of Mexico.

The reſt of it is diſtinguiſhed in the high mountain-peaks of the iſland of Margaretha, (Macanao and the Valle S. Juan,) and in the cordillera of the Iſthmus of Araya, which contains the micaceous ſchiſtous mountains of Maniguares, Chuparipari, Diſtilador, Cerro- Grande, the mountain of St. Joſeph and of Paria: the remainder I have accurately examined, and found in them the ſame ſtructure, the ſame direction, and the ſame inclination of the ſtrata.

The three hollows, or valleys of Caracas, Aragua, and Monai, are remarkable on this account, that the level of them is above the ſurface of the ſea; they become lower by gradations, and the higheſt ſtep is the eaſtern, which may ſerve as a proof that they were formed at an earlier period than the Llanos, whoſe declivity proceeds from eaſt to weſt, like the whole continent of South America. By repeated barometric meaſurement I found the height of the valleys of Caracas to be 416 toiſes, of Aragua 212 toiſes, above the ſurface of the ſea; the Llanos of Monai, the weſtern baſon, appears to have an elevation of no more than eighty or one hundred toiſes.— The valley of Caracas has once been a lake, which formed for itſelf an efflux through the Quebrada de Tipe, Catia, and Rio Mamon; the baſon of Aragua appears, on the other hand, to have become dry by gradual evaporation; for the remains of the old water (loaded with muriate of lime,) are ſtill ſeen in the lake of Valencia, which becomes leſs every year, and diſcovers iſlands which are known under the name of Aparecidas.— The height of the cordillera of the coaſt is commonly from 600 to 800 toiſes; the higheſt peaks, Sierra de Nevada de Merida and the Silla de Caracas, (to which we undertook a laborious journey with our inſtruments,) are 2350 and 1316 toiſes in height.

To the weſt they always become lower, and the height of Cape Codera is only 176 toiſes.

The Macanao, on the iſland Margaretha, which I meaſured trigonometrically, is not more in height than 342 toiſes; but this ſpeedy depreſſion takes place only in the primitive mountains of the cordillera.

On the eaſtern coaſt ſecondary accumulations of lime riſe from Cape Unare to a more conſiderable height than the gneis and micaceous ſchiſtus; theſe calcareous rocks, which are covered with ſandſtone of a calcareous baſe, and which accompany the cordillera of the coaſt in its ſouthern declivity, are very low on the ſide towards Cura, but riſe in a maſs towards the eaſtern extremity of the continent.

In Bergantin they are 702 toiſes high, in Coccollard 392, in Cucurucho du Tuminiquiri (the higheſt ſummits of the province of Cumana) 976 toiſes, and the pyramid of the Guacharo riſes above 820 toiſes: from Cape Unare they form a ſeparate ridge of mountains, in which the original ridge totally diſappears; they are connected alſo with the micaceous ſchiſtous cordillera of Maniquare and Paria only by the Cerro de Meapire, which, analogous to the branches of Torito and los Teques, which ſeparate the baſons of Monai, Aragua, and Caracas, extends north and ſouth from Guacharo and Catouaro, to the mountain Paria, and ſeparates the valley of Cariaco (the driedup bank of the Gulf of Cariaco) from the valley of St. Boniface, which formerly belonged to the Golfo Triſte.

It will be ſeen hereafter, that the accumulation of calcareous formation on the eaſtern part of the coaſt of this country ſeems to have been more expoſed to earthquakes; and that the Cerro de Meapire, at the time of the irruption of the Gulf of Cariaco, and the Golfo Triſte, prevented the water from converting the land of Araya and the ridge of Paria into an iſland.

The declivity of the cordillera of the coaſt of Venezuela is gentler towards the ſouth than towards the north, which is particularly ſtriking when one deſcends from the heights of Guigue, through St. Juan, Parapara, and Ortiz, towards the Mera de Paja, which belongs to the great Llano de Calabozo.

The northern declivity is every where very ſteep, and there is ſcarcely found, Mont Blanc excepted, above Courmayeur, a more frightful precipice than the perpendicular wall of Silla de Caracas, beyond Caravalledo, which riſes to the height of 1300 toiſes.

An accurate meaſurement of this wall of rock was of great importance to navigators, as they could find its diſtance from the coaſt only by taking the angle of its elevation: its longitude, therefore, of 60° 37′ 32″ weſt from Paris will enable them to diſcover it.

The phenomenon of a more gentle declivity towards the ſouth ſeems to contradict the obſervations made in other cordilleras of the earth, as it is aſſerted that they all decline more abruptly towards the ſouth and weſt.

This contradiction, however, is only apparent; as the northern part of the cordillera, during the great cataſtrophe which produced the Gulf of of Mexico, was torn away by the force of the water; and therefore the northern declivity might at that time be gentler than the ſouthern.

If the form of the coaſt be conſidered, it appears to be pretty regularly indented.

The headlands of Tres Puntas, Codera, S. Roman, and Chichibacoa, on the weſt, from Cabo de la Vela, form a row of promontories, the weſtern of which runs more to the north than the eaſtern.

To the windward of each of theſe capes a creek has been formed; and one cannot help ſeeing, in this ſingular formation, the action of the tropical currents, which may be called the currents of the earth’s rotation; an action which ſhews itſelf alſo in the direction of the coaſt from Cuba, St. Domingo, Porto Rico, Yucatan, and Honduras, as in the ſeries of the Windward Iſlands, Grenada, Orchila, Rocca, Aves, Buenos-Ayres, Curaçoa, and Aruba, the ruins of the cordillera from Cape Chichibacoa, which are all parallel to the equator.

It was this headland of Chichibacoa, notwithſtanding its inconſiderable height, which, by its reſiſtance to the influx, preſerved the kingdom of New Grenada from loſing ſo much land as the general government of Caracas.

The ſecond original cordillera of South America, which I have called the cordillera of the Cataracts of Orinoco, is yet very little known.

During the journey which we made on the Black River, to the borders of the Great Bara, we travelled more than two hundred leagues, firſt from north to ſouth, from Cerro de Uruana to Atabapo and Tuamini; then from weſt to eaſt, from the mouths of the Ventuari to Vulcan de Duida, which I have found to be in latitude 3° 13′ 26″, and longitude 60° 34′ 7″ weſt from Paris.

Since the journey of Meſſrs. Ituriaga and Solano, a paſſage over theſe cordilleras, which may be called alſo Parima or Dorado, (Golden) a name which has occaſioned ſo much misſortune in America, and ſo much ridicule in Europe, has been poſſible; but as all the European ſettlements on the Alto Orinoco, and the Rio Negro, (Black River,) contain at this time no more than four hundred Indian families; and as the way from Eſmeralde to Erevato and Caura has been totally loſt, our reſearches in a land ſo little civilized preſented more difficulties than Condamine experienced during his tedious navigation on the river Amazon, the banks of which for many years have been inhabited.

The cordillera of the Cataracts, or of Parima, ſeparates itſelf from the Andes of Quito and Popayan, in the longitude of from 3° to 6°. It extends from weſt to eaſt, from Paramo de Tuquillo and St. Martin, or the ſources of the Guaviare, the theatre of the gallant deeds of Philip de Urre, and the old reſidence of the Orneguas, through Morocote, Piramena, and Macuco, ſtretching through the country of the Indians of Guajibos, Sagi, Dagueres, and Poigraves, according to the direction of the great rivers Meta, Vichada, Zama, Guaviere, and Ymerida, in the longitude of 70° weſt from Paris, between the high ſummits of Uniama and Cunavami.

They form the Raudals of Atures and Maypuré, tremendous waterfalls, which afford the only paſſage by which one can penetrate into the interior of the land in the valley of the River Amazons.

Theſe Cordilleras of the Cataracts riſe from the longitude of 70°, and ſpread out in ſuch a manner that they comprehend the whole immenſe tract of country between the rivers Caura, Erevato, Cavony, Paraguamuſi, Ventuari, Jao, Padamo, and Manariche, and then aſcend ſouth towards the ſources of the Paſimona, Cachevaynris, and Cababury, towards the foreſts, where the Portugueze, penetrating into the Spaniſh diſtricts, collect the beſt ſarſaparilla known (Smilax Sarſaparilla.

Linn.).

In this diſtrict the cordilleras of the Cataracts are above one hundred and twenty miles in breadth.

Their continuation more towards the eaſt, between the longitude of 68° and 60° weſt from Paris, is little known.

I proceeded with aſtronomical inſtruments only, as far as Rio Guapo, which diſcharges itſelf into the Orinoco, oppoſite the Cerro de la Cauclilla, in longitude 68° 33′ weſt from Paris.

The Indians of Catarapeni and Maquiritares, who reſide in the ſmall miſſion of Eſmeralde, came fifteen miles further eaſt over the mountains Guanaja and Yamariquin to the Canno Chiguire; but neither the Europeans, nor Indians with whom Europeans have had any intercourſe, are acquainted with this ſource of the Orinoco, which is here called Canno Paragua, and is ſcarcely 150 or 200 toiſes in breadth, whereas at Boca de Apuré, in latitude 7° 32′ 20″, it is 4632 toiſes, as I myſelf found.

The wildneſs of the Indians of Guaicas, who are only four feet in height, but who are a very white and warlike people, and particularly the ſavage ſtate of the Guajaribos, greater men-eaters than any of the other nations which we viſited, prevent any one from penetrating over the ſmall cataracts (Raudal de Guajaribos,) eaſt from Chiguire, unleſs a military expedition were undertaken on purpoſe.

But by the wonderful journey undertaken by D. Antonio Santos, who married Onotho, and who dreſſed ſometimes as a Carib, and ſometimes as a Macacy, whoſe languages he ſpoke, from Orinoco (the mouth of the Rio Caronis) to the ſmall lake Parima and the river Amazon, we have obtained information reſpecting the continuation of the cordillera of the Cataracts.

Under the latitude of from 4° to 5° and longitude 63°, it becomes ſo narrow that it is ſcarcely ſixty miles in breadth.

It aſſumes here the name of Cerrania de Quimiropaca and Pacaraimo, and forms a chain of not very high ridges, by which the waters were divided.

The water of the northern declivity, the Nocapray, Paraguamuci, Benamo, and Mazurini, flow towards the Orinoco and Rio Eſquibo; the waters of the ſouthern, the Rio Curuicana, Parime, Madari, and Mao, pour themſelves into the River Amazon.

Some degrees further towards the eaſt, the cordillera again extends in breadth as it aſcends ſouthwards towards the Canno Parara along the Mao.

It is here that the Dutch give to the Cerro d’Ucuamo the magnificent name of the Gold Mountain, or Dorado, becauſe it conſiſts of a very ſhining micaceous ſchiſtus, a foſſil which has brought into celebrity the ſmall iſland of Ypamucena in the Lake of Parima.