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Alexander von Humboldt: „Sketch of a Geological Delineation of South America“, in: ders., Sämtliche Schriften digital, herausgegeben von Oliver Lubrich und Thomas Nehrlich, Universität Bern 2021. URL: <https://humboldt.unibe.ch/text/1801-Esquisse_d_un-4> [abgerufen am 15.07.2024].

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Titel Sketch of a Geological Delineation of South America
Jahr 1804
Ort London
Nachweis
in: The Philosophical Magazine 17:68 (Januar 1804), S. 347–357; 18:69 (Februar 1804), S. 26–36; 18:70 (März 1804), S. 172–179, Tafel.
Sprache Englisch
Typografischer Befund Antiqua; Auszeichnung: Kursivierung; Fußnoten mit Asterisken; Schmuck: Initialen.
Identifikation
Textnummer Druckausgabe: II.8
Dateiname: 1801-Esquisse_d_un-4
Statistiken
Seitenanzahl: 30
Zeichenanzahl: 72364

Weitere Fassungen
Esquisse d’un tableau géologique de l’Amérique méridionale (Paris, 1801, Französisch)
Skizze einer Geologischen Schilderung des südlichen Amerika (Weimar, 1802, Deutsch)
[Esquisse d’un tableau géologique de l’Amérique méridionale] (Salzburg, 1803, Deutsch)
Sketch of a Geological Delineation of South America (London, 1804, Englisch)
Geological Description of South America (London, 1804, Englisch)
Geognostische Skizze von Südamerika, von Alexander von Humboldt, mit erläuternden Bemerkungen des Herausgebers (Halle, 1804, Deutsch)
|347|

Sketch of a Geological Delineation of South Ame-rica. By F. A. Von Humboldt *.

Since I sent to Madrid the two first sketches of a geolo-gical delineation of South America, from the Caraccas andNueva Valencia, I have travelled 1200 miles, and describeda square between Caribe, Portocabello, Pimichin, and Es-meralda, a space comprehending above 59000 square miles,for I am not acquainted with the land between the moun-tain Parea and Portocabello, and between the northerncoast and the valley of the Black river. In consequence ofthe great circumference of this district, I must content my-self with delineating it in a general manner, and to avoiddetails, with describing the construction of the earth, thedeclivity of the land, the direction and inclination of themountains, their relative ages, their similarity with theformation of those in Europe. These are the circumstancesmost necessary to be known in this science. We mustproceed in mineralogy as in geography; we are acquaintedwith stones, but not with mountains; we know the mate-rials, but we are ignorant of the whole of which they formcomponent parts. I wish I may be able, amidst the variety
* This sketch is an extract from a paper transmitted by M. VonHumboldt from South America, together with a geological collection, tothe directors of the cabinet of natural history at Madrid. It was sentalso by M. Von Humboldt to Delametherie, and inserted by him in the Journal de Physique, vol. 53. p. 30.
|348| of the objects which occupy my attention during my tra-vels, to throw any light on the structure of the earth.The laborious journeys which, for eight years, I have madethrough Europe, had no other object; and if I have thegood fortune to return to Europe, and to recover my geo-logical manuscripts which I left behind me in France andGermany, I shall venture to give a sketch of the structureof the earth. What I have long said, that the directionand inclination, the rising and falling of the primitivestrata, the angles which they form, with the meridian ofthe place, and with the axis of the earth, are independentof the direction and depression of the mountains; that theydepend on laws, and that they observe a general parallelismwhich can be founded only in the motion and rotation ofthe earth. What Freiesleben, Von Buch and Gruner haveproved better than I will be found confirmed, namely, thatthe succession of the alluvial strata, which was consideredas a peculiarity of certain provinces, such as Thuringia andDerbyshire, takes place generally, and that there appearsan identity in the order of the strata (see Plate IX.); fromwhich there is reason to conclude that the same depositionhas been effected at the same time over the whole surface ofthe earth. All these ideas are of the greatest importance,not only to the philosopher, who endeavours to elevatehimself to general principles, but also to the miner, whomust conceive in his mind what he has not before his eyes,and guide himself by analogy deduced from actual ex-perience.
Before I describe the situation of the mountains which Ihave 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 aground for this description. For half a century past manyaccidental observations respecting this land have been col-lected, but not a single idea relating to its geology has beenmade known. The great genius of Condamine, the zealof Don George Juan de Ulloa, would certainly not haveleft us in the dark on this subject, had mineralogy beenmore cultivated at the time when they wrote. All thatcould then be done was to measure and to take levels. Asthey were employed on the high cordillera of the Andes,which extends north and south from Zitara, as far as CapePilar, and beheld with wonder the immense height of themountains, they forgot that South America exhibits othercordilleras, which extend east and west parallel to the equator, and which, on account of their height, deserve as |349| much the attention of naturalists as the Carpathians, Cau-casus, the Alps of the Valais, and the Pyrenees. Thewhole immense tract on the west side of the Andes, whichextends obliquely to the coast of Guiana and Brasil, is de-scribed as a low plain, exposed to the inundation of therivers. As only a few Franciscan missionaries and a fewsoldiers have been able to penetrate over the cataracts toRio Negro, the inhabitants of the coast of Caracas ima-gine that the immense plains (the Llanos de Calabozo, delGuarico, and de Apure) which they see to the south, be-yond the valleys of Aragua, extend without interruption tothe Pampas of Buenos-Ayres, and to the country of thePatagonians; but the extent of these plains is far frombeing so great; they are not uninterrupted plains, they arerather phenomena of the same kind as those presented byCanada and Yucatan, the Island of St. Domingo, the northof Sierra de St. Martha, the province of Barcelona, and theland 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, andare as far from lying in the same plane as the deserts of Africa, and the steppes of Tartary, which rise by grada-tions, 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, thedirection of its cordilleras appears not to be very differentfrom that of those in the new world, as most naturalistshave asserted. We are acquainted also with the traces ofseveral high chains of mountains which extend from northto south, and run out from those which extend east andwest. The garnet and micaceous schistus of Norway,Scotland, Wales, Brittany, the province of Gallicia, Alem-tego, Cape Bogador, (I have found the same with graniteon Teneriff,) the upper part of Guinea, Congo, and theTable Mountain, as also the original mountains of Oren-burg, Caucasus, Lebanon, of Abyssinia and Madagascar,seem at first to have formed nothing else than two largecordilleras parallel to the meridian. In the new world these cordilleras run parallel to themeridian from Cape Pilar to the north of California beyondNootka and Prince William’s sound towards the Aleganheymountains, which were discovered in 1792 by Mr. Stewart on his journey to the sources of the Missoury, the northernpart of the Andes, which is inhabited by Indians nearly asmuch civilized as the Peruvians were fifteen hundred yearsago. From this cordillera proceed ramifications of the |350| original mountains which extend from west to east. Withthose of North America I am not acquainted, but it appearsthat some exist in Canada under the latitude of 50° and42° north latitude, as in the destroyed continent of theGulph of Mexico under 19° and 22°, as is proved by themountains of Cuba and Saint Domingo. In South Ame-rica there are three chains of original mountains which runparallel to the equator: the chain of the coast under 9° and10°; that chain which is in the great cataracts of Autures(in latitude 5° 39′) is between latitude 3° and 7°; and thatin Maipure in 5° 12′ 50″, which I therefore call the chainof the cataracts or that of Parime, and the chain of Che-quitos under 15° and 20° south latitude. These chains in the old continent on this side of thewestern ocean can be traced, and it is seen how the originalmountains of Fernambouc, Minas, La Bahia, and Janeiro,correspond, under the same latitude, to those of Congo, asthe immense plains near the river Amazon lie opposite tothe plains of Lower Guinea, the cordillera of the cataractsopposite to those of Upper Guinea, and the Llanos of theMississippi, since the irruption of the Gulph of Mexico, aproperty of the sea, opposite to the Desart of Serah. Thisview will appear to be less hazarded when one reflects inwhat manner the old continent has been separated from thenew 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. Whatwe call the Atlantic ocean is nothing else than a valleyscooped out by the sea. The pyramidal form of all thecontinents with their summits turned southwards, the greatflattening of the earth at the south pole, and other phæno-mena, observed by Dr. Forster, seem to show that the in-flux of the water was from the south. On the coast ofBrasil, from Rio Janiero to Fernambouc, it found resist-ance, and taking a direction from the latitude of 50° northtowards the north-east, where it scooped out the Gulf ofGuinea near Loango, Benin and Minc, it was obliged bythe mountains of Upper Guinea to direct itself north-west,and separated, to the latitude of 23° north, the coast of Gui-nea from Mexico and Florida. The force of the waters wasstill broken by the cordillera of the United States of Ame-rica, and once more turned towards the north-east, andseems to have spared less the western coast of Europe thanthe northern of America. The least breadth of this channelis at the Brasils and Greenland; but, agreeably to the geo-graphical history of plants and animals, it seems to have |351| been formed at a time when the organic creation had notbeen properly expanded. It would be of great importanceto geology if a sea voyage were undertaken, at the expenseof some government, to examine the rising and depressionand the relative situation of the mountains to the salientand re-entering angles of America and Africa. The sameanalogy would be found here as is observed in the EnglishChannel, in the Sound, the Straits of Gibraltar, and theHellespont; small creeks which are as new as the secondaryformation of the chalk rocks of Jura, of Pappenheim, LaMancha, Marseilles, Derbyshire, and Suez, which have allbeen produced at the same time by precipitation. Of the three cordilleras of primitive mountains whichtraverse South America from west to east, the most north-ern, that of Venezuela, is the highest, but the narrowest.The real chain of the Andes extends from the large plainof Quito, through Popayan and Choco, to the western sideof the river Atrato (or Rio San Juan), between the valleyof Tatabé, in the provinces of Zitara and Biruguete, to-wards the isthmus, where it forms a mountainous districtof not more than two or three hundred toises in height onthe bank of the Chagre. From these Andes arises the cor-dillera on the coast of Venezuela. Rows of mountainshigher, but forming groups less regular, extend on theeast side of the Rio Atrato under the name of the Sierra deAbibé and the Montes de Cauca, through the high savan-nahs of Jolu towards Magdalen river and the province ofSt. Martha. The cordillera of the coast contracts itself likethat of the Gulph of Mexico, approaches nearer to CapeVela, and then proceeds first from south-south-west tonorth-north-east, and then from west to east to the ridgeof Paria, or rather to the Punta de la Galera in the Islandof Trinidad. Its greatest height is found at that placewhere it has the name of Sierra de Nevada de St. Martha inlatitude 10° 2′, and of Sierra Nevada de Merida in latitude8° 30′; the former is about 5000 the latter 5400 Spanishells (varas), or 2350 toises in height. The Paramo de laRosa and de Macuchi, and also the mountain of Merida,are continually covered with snow: boiling water (withhydrogenated sulphur) issues from their sides, and theyexceed in height the Peak of Teneriff, and are, perhaps,equal to Mont Blanc, which has been more accurately mea-sured. These colossal masses and St. Martha stand almostinsulated, being surrounded by few high ridges. To thewest of Santa Fé, or as far as the Sierra of Zuindiu, nosnow-clad peaks are seen, and the Sierra Nevada de Merida |352| stands at the edge of the plain of Caracas, which is scarcelyforty toises above the level of the sea. Mont Blanc, whichterminates the high ridge of the Alps, exhibits the samephænomenon. The altitude of the highest mountains,however, is so very small in proportion to the magnitudeof the earth that it would appear that very small local causesought to have accumulated more matter in these points.That part of the cordillera of the coast which lies to thewest of Maracaybo-Sees, and joins the Andes, has largevalleys extending from north to south, such as that of Mag-dalena, 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 ex-tends from Merida to Trinidad incloses three valleys lyingeast and west, which show by certain signs, like Bohemia,or the Haslithal of Swisserland, that they have formerlybeen lakes the water of which has evaporated or run off byopening for itself a passage. These three valleys are in-closed by the two parallel rows of mountains into whichthe cordillera of the coast divides itself, from Cape Vela toCape Codera; the northern row is a continuation of SaintMartha, the southern a prolongation of Sierra Nevada deMerida. The first extends through Burburuta, Rincon delDiablo; through the Sierras de Mariara, the mountainAguasnegras, Monte de Arila, and the Silla de Caracas, toCape Codera. The second from three to four miles moreto the south extends through Guigui, La Palma, the highsummits of Guairaima, Tiara, Guiripa, and the Savana deOcumare, as far as the mouths of the Tuy. These twochains unite with two arms which run from north to south,like, as it were, dykes, by which these old lakes were con-fined within their boundaries. These dykes are, on the westthe mountains of Carora, Torito, Saint Maria, Saint Phi-lips, and Aroa; they separate the Llanos de Monai fromthe valleys of Aragua: on the east they are the naked sum-mits of Los Teques, Coquiza, Buena Vista, and the Altosde S. Pedro, by which the valley of Aragua or the sourcesof the Tuy (for there is only one valley between the bottomof Coquiza or the Hacienda de Brisenno to Valencia) fromthe valley of Caracas. On the east from Cape Codera thegreater part of the cordillera of the coast of Venezuela wasdestroyed and laid under water by the great catastrophewhich formed the Gulph of Mexico. The rest of it is di-stinguished in the high mountain peaks of the Island ofMargaretha (Macanao and the Valle S. Juan) and in thecordillera of the Isthmus of Araya, which contains the |353| micaceous schistous mountains of Maniguares, Chuparipari,Distilador, Cerro-Grande, the mountain of St. Joseph and ofParia: the remainder I have accurately examined, and foundin them the same structure, the same direction, and the sameinclination of the strata. The three hollows, or valleys ofCaracas, Aragua, and Monai, are remarkable on this ac-count, that the level of them is above the surface of thesea; they become lower by gradations, and the highest stepis the eastern, which may serve as a proof that they wereformed at an earlier period than the Llanos, whose decli-vity proceeds from east to west, like the whole continentof South America. By repeated barometric measurementI found the height of the valleys of Caracas to be 416toises, of Aragua 212 toises, above the surface of the sea;the Llanos of Monai, the western bason, appears to havean elevation of no more than 80 or 100 toises. The valleyof Caracas has once been a lake, which formed for itselfan efflux through the Quebrada de Tipe, Catia, and RioMamon; the bason of Aragua appears, on the other hand,to have become dry by gradual evaporation; for the remainsof the old water (loaded with muriate of lime) are still seenin the lake of Valencia, which becomes less every year, anddiscovers islands which are known under the name of Apa-recidas. The height of the cordillera of the coast is com-monly from 600 to 800 toises; the highest peaks, Sierrade Nevada de Merida and the Silla de Caracas, (to whichwe undertook a laborious journey with our instruments)are 2350 and 1316 toises in height. To the west they al-ways become lower, and the height of Cape Codera is only176 toises. The Macanao, on the island Margaretha,which I measured trigonometrically, is not more in heightthan 342 toises; but this speedy depression takes place onlyin the primitive mountains of the cordillera. On theeastern coast secondary accumulations of lime rise fromCape Unare to a more considerable height than the gneisand micaceous schistus; these calcareous rocks, which arecovered with sandstone of a calcareous base, and whichaccompany the cordillera of the coast in its southern decli-vity, are very low on the side towards Cura, but rise in amass 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 theprovince of Cumana) 976 toises, and the pyramid of theGuacharo rises above 820 toises: from Cape Unare theyform a separate ridge of mountains, in which the originalridge totally disappears; they are connected also with the |354| micaceous schistous cordillera of Maniquare and Paria onlyby the Cerro de Meapire, which, analogous to the branchesof Torito and los Teques, which separate the basons ofMonai, Aragua, and Caracas, extends north and southfrom Guacharo and Catouaro, to the mountain Paria, andseparates the valley of Cariaco (the dried up bank of theGulph of Cariaco) from the valley of St. Boniface, whichformerly belonged to the Golfo Triste. It will be seenhereafter, that the accumulation of calcareous formationon the eastern part of the coast of this country seems tohave been more exposed to earthquakes; and that the Cerrode Meapire, at the time of the irruption of the Gulph ofCariaco, and the Golfo Triste, prevented the water fromconverting the land of Araya and the ridge of Paria into anisland. The declivity of the cordillera of the coast of Venezuelais gentler towards the south than towards the north, whichis particularly striking when one descends from the heightsof Guigue, through St. Juan, Parapara, and Ortiz towardsthe Mera de Paja, which belongs to the great Llano deCalabozo. The northern declivity is every where verysteep, and there is scarcely found, Mont Blanc excepted,above Courmayeur, a more frighful precipice than the per-pendicular wall of Silla de Caracas, beyond Caravalledo,which rises to the height of 1300 toises. An accurate mea-surement of this wall of rock was of great importance tonavigators, as they could find its distance from the coastonly by taking the angle of its elevation: its longitude,therefore, of 60° 37′ 32″ west from Paris, will enable themto discover it. The phenomenon of a more gentle declivity towards thesouth seems to contradict the observations made in othercordilleras of the earth, as it is asserted that they all declinemore abruptly towards the south and west. This contra-diction, however, is only apparent as the northern part ofthe cordillera, during the great catastrophe which producedthe Gulph of Mexico, was torn away by the force of thewater; and therefore the northern declivity might at thattime be gentler than the southern. If the form of the coast be considered, it appears to bepretty regularly indented. The headlands of Tres Puntas,Codera, S. Roman, and Chichibacoa, on the west, fromCabo de la Vela, form a row of promontories, the westernof which runs more to the north than the eastern. To thewindward of each of these capes a creek has been formed;and one cannot help seeing, in this singular formation, the |355| action of the tropical currents, which may be called thecurrents of the earth’s rotation; an action which shows it-self also in the direction of the coast from Cuba, St. Do-mingo, Porto Rico, Yucatan, and Honduras, as in the se-ries of the windward islands Grenada, Orchila, Rocca, Aves,Buenos-Ayres, Curaçoa, and Aruba, the ruins of the cor-dillera from Cape Chichibacoa, which are all parallel tothe equator. It was this headland of Chichibacoa, not-withstanding its inconsiderable height, which by its resist-ance to the influx, preserved the kingdom of New Grenadafrom losing so much land as the general government ofCaracas. The second original cordillera of South America, whichI have called the cordillera of the Cataracts of Orinoco, isyet very little known. During the journey which we madeon the Black River, to the borders of the Great Bara, wetravelled more than 200 leagues, first from north to south,from Cerro de Uruana to Atabapo and Tuamini; then fromwest to east, from the mouths of the Ventuari to Vulcande Duida, which I have found to be in latitude 3° 13′ 26″,and longitude 60° 34′ 7″ west from Paris. Since the jour-ney of Messrs. Ituriaga and Solano, a passage over thesecordilleras, which may be called also Parima or Dorado(golden), a name which has occasioned so much misfortunein America, and so much ridicule in Europe, has been pos-sible; but as all the European settlements on the AltoOrinoco, and the Rio Negro (Black River), contain atthis time no more than 400 Indian families, and as theway from Esmeralde to Erevato and Caura has been totallylost, our researches in a land so little civilized, presentedmore difficulties than Condamine experienced during histedious navigation on the river Amazon, the banks of whichfor many years have been inhabited. The cordillera of the Cataracts or of Parima separatesitself from the Andes of Quito and Popayan, in the longi-tude of from 3° to 6°. It extends from west to east fromParamo de Tuquillo and St. Martin, or the sources of theGuaviare, 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 ofthe Indians of Guajibos, Sagi, Dagueres, and Poigraves,according to the direction of the great rivers Meta, Vichada,Zama, Guaviare, and Ymerida, in the longitude of 70° westfrom Paris, between the high summits of Uniama and Cu-navami. They form the Raudals of Atures and Maypuré,tremendous waterfalls, which afford the only passage by |356| 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 longitudeof 70°, and spread out in such a manner that they compre-hend the whole immense tract of country between the riversCaura, Erevato, Cavony, Paraguamusi, Ventuari, Jao, Pa-damo, and Manariche, and then ascend south towards thesources of the Pasimona, Cachevayneris, and Cababury,towards the forests, where the Portugueze, penetrating intothe Spanish district, collect the best sarsaparilla known(Smilax Sarsaparilla, Linn. ). In this district the cordillerasof the Cataracts are above 120 miles in breadth. Theircontinuation more towards the east, between the longitudeof 68° and 60° west from Paris is little known. I pro-ceeded with astronomical instruments only, as far as RioGuapo, which discharges itself into the Orinoco, oppositethe Cerro de la Cauclilla, in longitude 68° 33′ west fromParis. The Indians of Catarapeni and Maquiritares, whoreside in the small mission of Esmeralde came fifteen milesfurther east over the mountains Guanaja and Yamariquinto the Canno Chiguire; but neither the Europeans, nor In-dians with whom Europeans have had any intercourse, areacquainted with this source of the Orinoco, which is herecalled Canno Paragua, and is scarcely 150 or 200 toises inbreadth, whereas at Boca de Apuré, in latitude 7° 32′ 20″,it is 4632 toises, as I myself found. The wildness of theIndians of Guaicas, who are only four feet in height, butwho are a very white and warlike people, and particularly thesavage state of the Guajaribos, greater men-eaters than anyof the other nations which we visited, prevent any one frompenetrating over the small cataracts (Raudal de Guajaribos)east from Chiguire, unless a military expedition were un-dertaken on purpose. But by the wonderful journeyundertaken by D. Antonio Santos, who married Onotho,and who dressed sometimes as a Carib, and sometimes asa Macacy, whose languages he spoke, from Orinoco (themouth of the Rio Caronis) to the small lake Parima andthe river Amazon, we have obtained information respect-ing the continuation of the cordillera of the Cataracts.Under the latitude of from 4° to 5° and longitude 63°, itbecomes so narrow that it is scarcely 60 miles in breadth.It assumes here the name of Cerrania de Quimiropaca andPacaraimo, and forms a chain of not very high ridges, bywhich the waters were divided. The water of the northerndeclivity, the Nocapray, Paraguamuci, Benamo, and Ma-zurini, flow towards the Orinoco and Rio Esquibo; the |357| waters of the southern, the Rio Cururicana, Parime, Madari,and Mao, pour themselves into the River Amazon. Somedegrees further towards the east, the cordillera again extendsin breadth as it ascends southwards towards the Canno Pa-rara along the Mao. It is here that the Dutch give to theCerro d’Ucuamo, the magnificent name of the Gold-Mountain, or Dorado, because it consists of a very shiningmicaceous schistus, a fossil which has brought into celebritythe small island of Ypamucena in the lake of Parima. On the east from Rio Esquibo, or on the other side ofthe land of the Aturajo Indians the cordillera turns south-east as it unites with the garnet mountains of the Dutchand French Guiana, which are inhabited by a mixture ofNegroes and Caribs, and give an origin to the rivers Ber-bice, Surinam, Marony, Aprouague, and Oyapock. Thelast mentioned ridge of mountains extends very much: itsgneis appears at Baxo Orinoco, in latitude 8° 20′, betweenthe mouths of the Upata and Acquire, and in latitude2° 14′ on the north side of the river Amazon, in the moun-tains of Fripoupon and Maya. Such is the form of the great cordilleras of the Cataracts,which are inhabited by a great number of uncivilizedsavages, little known to the Europeans. I must here ob-serve, that in this description I have followed my ownobservations only, and the notices we obtained from theIndians, as also the observations of D. Antonio Santos, andthe companions of his journey, who dictated to theirfriends. The maps of this part of the continent are en-tirely false, and the map added to the history of the Evir-coco by P. Caulin, a work in other respects meritorious, isby our last observations some degrees more wrong in longi-tude and latitude than the map published thirty years be-fore by d’Anville. All the Indian names in it also are mu-tilated, and mountains and rivers are delineated where noneexist; a defect the more pardonable as the author was neverbeyond the waterfalls of Orinoco, nor at the Rio Negro. [To be continued.]
|26|

Sketch of a Geological Delineation of South America.By F. A. Von Humboldt.

[Continued from our last volume, p. 357.] The cordillera of Parima never reaches to the same heightas the Sierra Nevada in the province of Caraccas, which is2350 toises. Their highest summit seems to be the Cerrode la Esmeralda, or the mountain Duida, which, by trigo-nometrical measurement, I found to be 1323 toises abovethe surface of the sea, which is the height also of the Ca-nigou. This mountain is situated in a delightful plain co-vered with ananas and palms: the monstrous mass whichit exhibits towards the Mission and the rivers Canu-canumaand Tamatama, and the flames it vomits up towards theend of the rainy season, give it a romantic and majestic ap-pearance. No Indian is able to clamber up to the top ofthis mountain and the rocks of its summit without a week’slabour, because the luxuriance of vegetation in this climateimpedes the progress of travelling. Next to the Duida, theMaraguaca, more towards the east of the river Simirimóni,and the high cordillera of Cunarami and Calitamini, whichat Maypuré and St. Barbara is known under the false nameof Sipapo, are the highest summits of the chain; they arefrom 1000 to 1100 toises in height. The common heightof the cordillera, however, does not exceed 600 toises, andsometimes it is less, as the part situated between the leftbank of the Cassiguiaré, an arm of the Orinoco whichconnects together the Rio Negro and the river Amazon,and the sources of the cataracts and Piramena between Ca-richana and Morocote, is destroyed, and still exhibits insu-lated rocks rising from the ground. The cause of this de-struction seems to have been an eruption of water from thebason of the Amazon river towards the bason of Calabozoand Baxo-orinoco, which differ in height about 160 toises. The geological chart of this district which I have con-structed represents an immense valley which unites theLlanos of the Rio Negro, Cassiguiaré, and Amazon, withthose of the province of Caraccas, Barcelona, and Cumana;a valley which sinks down towards the north, and is inter-sected by a large series of single rocks which show the di-rection of the old cordillera on the banks of the Guaviareand Nuta in the province of Cassemora. The eastern ex-tremity of this valley is the lowest part of it, and thereforethe remains of the water of the Orinoco cut out for itself a |27| bed in this place. This cordillera has two remarkableproperties. In the first place, as has been remarked inother ridges, the southern declivity is much steeper thanthe northern: the high summits of Caravami, Jao, of thevolcano of Duida, Maraguaca, &c., all lie towards thesouth, and are there cut into perpendicular precipices. Inthe second place, this cordillera does not seem to contain asingle rock of alluvial mountains, and consequently has bor-rowed nothing from the organized kingdom. On our pas-sage over this ridge we observed nothing but granite, gnieis,micaceous schist, and hornblend schist; nowhere a coveringof sand-stone or alluvial chalk, which on the cordillera ofVenezuela on the coast rises to the height of 976 toisesabove the level of the sea. Had the proximity of the equator and the rotation of the earth any influence on this phæno-menon? The third chain of original mountains, the cordillera ofChiquitos, is known only from the accounts of some per-sons who have resided at Buenos-Ayres and travelledthrough the Pampas. It unites the Andes of Peru andChili with the ridges of Brasil and Paraguay as it stretchesfrom La Paz, Potosi, and Tucuman, through the provincesof Maxos, Chiquitos, and Chaco, towards the governmentof the Mines and of St. Paul in Brasil. Their highest sum-mits seem to be situated between the latitude of 15° and 20°south, as the streams between the rivers Amazon and LaPlata divide themselves at that height. Between the three cordilleras, the direction of which wehave hitherto followed, lie three broad and deep valleys.1st, The valley between the south side of the cordillera ofVenezuela, on the coast, and the cordillera of the Cataracts,or the valley of Orinoco and Apuré, between latitude 8°and 10°. 2d, The valley of the rivers Negro and Amazon,bordered by the Parima ridge and the cordillera of Chiqui-tos, between latitude 3° north and 10° south. 3d, The val-ley of Pampas of Buenos-Ayres, which extends from SaintCruz of Sierra to Cape Virgin, between 19° and 52° southlatitude. The first and second valley are in some measureunited by the destruction of a part of the Parima cordillera.I do not know whether this be the case also with the Pampasand valley of the Amazon; it, however, appears that it isnot, though the Llanos of Monso form a sort of canal whichdescends from north-west to south-east. All these immensevalleys or plains are entirely open towards the east, as theyrun out into a low sandy coast: towards the west they areshut by the chain of the high Andes. There are some creeks |28| (anses) which proceed from east to west in the direction ofthe tropical current, and on that account extend furtherinto the land the broader the continent is. The valleys of Apuré and Orinoco are closed by the ridge which extendsfrom Pampelona to Merida in longitude 73°, and the val-ley of Pampas in longitude 70°: they both fall together alittle towards the east, and seem to be covered by one andthe same formation of alluvial strata. Tralles says, that in Swisserland there is more reason towonder at the depth of the lakes than at the height of themountains: I will venture to make a similar observation inregard to the Llanos or plains of South America. Howastonishing it is to see a continent which in its inte-rior parts several hundred miles from the coast, and in theneighbourhood of mountains 3000 toises in height, is ele-vated scarcely fifty toises above the surface of the sea! Ifthe flux in these places should rise to as great a height asat St. Malo and Bristol, and if more motion should becommunicated to the ocean by earthquakes, the greaterpart of these valleys would be laid under water. Thehighest Llano which I have measured is that between therivers Ymirida, Temi, Pimichia, Cassiguiaré, and Guiainia(Rio Negro); it is 180 toises in height; but it sinks downtowards Atures in the north, as towards the river Amazon in the south. The valley of Orinoco and Apuré is stillmuch lower than that of Cassiguiare and Calabozo in themiddle of the Llano where I made observations, in latitude8° 56′ 56″ and longitude 70° 9′ west from Paris. At An-gostura, the capital of Guyana, latitude 8° 8′ 24″, longitude66°, it is only 33 toises, and eighty miles from the coastscarcely eight toises above the level of the sea. The plainsof Lombardy, in Europe, have the greatest resemblance tothe Llanos on account of their small elevation. Pavia isonly 34, and Cremona 24 toises in height; the other plainsof Europe have a much greater elevation. In Saxony andLower Silesia the plains are only from 87 to 120 toisesin height; those of Bavaria and Swabia are from 230 to250. The declivity of the Llanos of America is so gentle,their inequalities are so imperceptible, that no large riverflows to either side. The Orinoco appears in the longitudeof about 70°, as if about to discharge itself in the sea towardsPortobello; but at Cabrouta it turns to the east without theleast obstacle being discovered either there or at St. Fernandode Atabapo, in latitude 7° 55′ 8″, to oppose its course. Inthe large valley of Rio Negro, and of the Amazon river, isa tract of land, in 2° or 3° north latitude, of not less than |29| 1600 square miles, which is bordered by the large riversAtabasso, Cassiguiaré, Guiainia, and Orinoco, and repre-sents a parallelogram, in which the water flows on the fouropposite sides in opposite directions. In regard to the Ori-noco, I found a fall of 151 toises in the distance of 70 milesfrom the mouth of Guaviare to the Apuré; but from thecapital to the sea not more than eight toises. La Conda-mine observed the same thing in regard to the river Ama-zon, from the narrow pass of Paucis to Para, where it runsthrough a district of 240 miles, but falls not more than 14toises. It is not improbable that there might have beenon the north side of the cordillera of the coast of Venezuelaa plain as much lower than the plain of Orinoco as the plainof Rio Negro is higher than that of Orinoco, and on thisaccount the former plain was covered by the water of thebay. The two Llanos or plains which lie at the opposite ex-tremities of America exhibit a striking difference from thatwhich lies between them, namely, the vale of the riverAmazon. The latter is covered by so impenetrable foreststhat rivers alone can force a passage through them, and thatscarcely any other animals but such as frequent trees canlive in that district; so much is vegetation favoured by thecontinual rains under the equator. The case is quite dif-ferent with the plains of Orinoco and Pampas; they arelevel valleys covered with herbs, and savannahs which con-tain only a few scattered palm-trees. The same heat, thesame want of water, and the same phænomena of refrac-tion, that is to say, the inverted image of objects seen float-ing in the atmosphere, are observed here as in the desertsofAfricaand Arabia. But plains so perfect are nowhereelse to be found; for the Mesa de Pavone and the Mesa deGuanipa in 800 square miles contain no eminence of eightor ten inches in height. The plains of Lower Hungary,on the west of Presburgh, have the greatest resemblance tothem; for the flat land of La Mancha, Champagne, Westpha-lia, Brandenburgh, and Poland, is hilly when compared withthe Llanos of South America. Nothing but a long stagna-tion of water could have produced so horizontal a bottom.Traces of old cities are found here, but seldom are any seenwhich rise like castles (La Piedra Guanan, longitude 69° 3′,latitude 1° 59′ 48″) in the Llano of Cassiguiaré and of RioNegro. But from St. Borja to the mouth of the Black river Condamine observed no eminence; and the Llano of Ori-noco is also without islands. As the Morros of San Juanbelong to the southern declivity of the cordillera of Vene- |30| zuola, an impetuous current of water must have swept everything along with it; and the present sea presents large spaceswithout islands: instead of islands there are in the Llanoswhole uninterrupted portions of from 200 to 300 squaremiles of surface which rise from two to five feet above theplain, and which are called mesas or bancos; which is asmuch as to say, that they were shoals or sand-banks in theantient sea. I must here observe, that the middle of theplain of Orinoco is the most beautiful and levellest part ofit. The bottom of this immense bason rises up and becomesunequal at the edge; the plains therefore which one tra-verses between Guyana and Barcelona are less perfect andlevel than those of Calabozo and Uritucu. This remarkable difference which we found between thecordillera of Venezuola and that of the Cataracts, which isthat the latter consist of alluvial mountains entirely bare, isobserved between the northern Llano of the Orinoco and thatof the Rio Negro and river Amazon. In the former, theoriginal mountains are every where covered with compactlimestone, gypsum, and sandstone: in the latter the gra-nite every where appears. The more one approaches the equator the thinner is the stratum of sand which covers thecrust of earth on the original mountains: in a land wherevegetation is so luxuriant, there is seen in the middle of fo-rests spaces of 40,000 square toises scarcely covered witha few lichens, and which do not rise two inches above therest of the surface. Will the same be discovered in Africa?for it is only in America and Africa that there is land underthe equator. Having taken a view of the direction of the mountainsand valleys, or the form of the inequalities of the earth, letus now turn our attention to objects of more importancewhich have been less examined, namely, the rising and fall-ing of the strata of the original mountains which formthis part of the earth I have traversed. I have been con-vinced since 1792 that the rising of the original mountainsfollows a general law, and that, making allowance for thoseinequalities which may have been produced by trifling localcauses, and particularly veins and strata in mines, or by veryold valleys, the stratified coarse-grained granite, the foli-ated granite, and particularly the micaceous schist and ar-gillaceous schist, rise in the league 3\( \frac{4}{8} \) by the miner’s com-pass, as they form with the meridian of the place an angleof 52\( \frac{1}{2} \)°. The falling of the strata is towards the north-west; that is to say, they fall parallel with a body thatmight be thrown in the same direction, or the aperture of |31| the angle of inclination (less than 90°) which it makes withthe earth’s axis stands towards the north-east. The rising ismore constant than the falling, especially in the simple moun-tains (argillaceous schist, hornblend schist), or in the com-pound mountains with fewer crystallized grains, such as themicaceous schist. In granite (it is, however, found very re-gularly stratified rising in the league 3 — 4, and falling to-wards the north on the Schneekopfe, the Ochsenkopfe, theSiebengebirge, and the Pyrenees,) and in the gnieis the at-traction of the crystallized mixed parts to each other seemsto have prevented the regular stratification; therefore morecoincidence is found among the micaceous and argillaceousschist, and these first led me to the idea of the law of risingduring my tour to the Fichtelberg and the Thuringian fo-rest. Since that time I have examined with great carethe angle of the strata of other original mountains in otherparts of Germany, in Swisserland, Italy, the southernparts of France, and the Pyrenees, and lately in Gallicia.Mr. Freiesleben, whose labours have been of so much ser-vice to geology, assisted me in this examination; and wewere astonished at the uniformity in the rising and fallingof the mountains which we found at each step on one ofthe highest cordilleras of the earth, the Alps of Savoy, theValais, and the Milanese. An examination of this phænomenon, and of the identityof the strata, was one of the principal objects when I under-took a voyage to America. A measurement of the angleswhich I have hitherto made on the cordillera of Venezuolaand Parima gave again the result of my observations inEurope in the chain of the micaceous schist mountains ofCavaralleda as far as Rio Mamon; on the Silla de Caracas atthe height of 1000 toises; of the Rincon del Diablo, onmount Guigue; in the islands in the beautiful lake of Va-lencia, which has almost the same elevation as the lake ofGeneva, at the boundaries of the isthmus of Maniguaré andChupariparu; on the hornblend schist which appears unco-vered in the streets of the capital of Guyana, and also in theCataracts, and on the stratified granite at the foot of theDuida. Every where the strata form an angle of 50° withthe meridian (in the league 3 — 4 by the Saxon compass) asthey rise from the north-east to south-west, and fall aboutfrom 60 to 80 towards the north-west. This great coincidence in the old and new world mustexcite serious considerations. It exhibits a very importantgeological fact. After so many observations which I havemade in places so far distant from each other, it can no |32| longer be believed that the rising of the strata follows thedirection of the cordillera, and that the falling follows thedeclivity of the mountains. The profile of many of themountains, particularly a section of the mountains, such asthat of Genoa through the Bochetta, and of St. Gothard asfar as Franconia in Germany, which I intend to publish ata proper time, proves exactly the contrary. The rising anddeclivity of the cordillera, the form of the small inequali-ties of the earth, seem to be newer phænomena. A streammight scoop out a valley in this or in that direction; mighttear asunder a part of the cordillera, and give it apparentlyone direction or another. The strata of the original moun-tains appear, amidst all these angles of rising and fallingobserved at present, to have existed before these changes atthe surface of the earth. They are the same at the summitof the Alps, and in the mines into which we descend.When one travels for 15 miles over strata of argillaceousschist, which are inclined parallel to each other, at an an-gle of 70° towards the north-west, one can no longer be-lieve that they are deranged strata, which once stood hori-zontal. We must suppose mountains that were once 15miles in height, and that the whole mass had an uniformfall, and then reflect on the space which such a mass wouldoccupy: and one must remember the strata on the heightsof Genoa, or on the heights of Bochetta, or on St. Maurice,which are exactly parallel; and on the strata of the Fich-telberg of Gallicia, the Silla de Caracas of Robolo on theisthmus of Araya of Cassiguiare, in the neighbourhood ofthe equator. One must allow that this coincidence givesevidence of a cause which has acted at a very early period,and in a general manner; a cause which must have arisenfrom the first attraction by which matter was forced toge-ther to form a spherical planet. This grand cause does not exclude local causes, by whichindividual smaller parts of matter were determined to ar-range themselves in this or in that manner, according tothe laws of crystallization. Delametherie has made an in-genious remark on this subject: he shows the influence ofa large mountain (as a small nucleus) on the neighbouringsmall mountains. One must not forget that, besides thegeneral attraction towards the centre, all matters exercise amutual attraction on each other. The crust of the earth, for I will venture to speak onlyof this part, must be the result of an immense action ofpowers of attraction of affinities, which determined, putin equilibrium, and modified each other. M. Klugel |33| thought he found, by calculation, that the great flatteningof the earth must be on the west side of the north pole.Has the axis of rotation been changed? What will be theinclination of the strata in the southern hemisphere? Weare not acquainted with the cause; let us rather continue toexamine the phænomena. This falling of the strata of the original mountains inthe cordillera of Venezuola has a great and melancholyinfluence on the fertility of the provinces of Caracas, Cu-mana, and Barcelona; the water which filtres through atthe summit of the mountain flows down according to thedirection of the strata, and for this reason there is greatwant of water in the whole large district which lies on thesouth side of the cordillera, and therefore so many springsand small streams burst forth on the northern declivity,which, by this great quantity of moisture, and the super-abundance of wood, which shelters it almost the whole dayfrom the sun’s rays, is rendered as unhealthful as it is fruit-ful. The alluvial mountains which I have hitherto observedare almost under the same circumstances as in Europe. Theoldest seem to have experienced the action of the samecauses which determined the strata of the original moun-tains, as they rise in the league 3—4, or as the seamen ex-press it, N. 50 E. They often fall towards the south-east,as in the Alps of Bern, the Valais, Tyrol, and Steyermark;but the greater part of them, and particularly the newest,which where I have been are the most numerous, followno certain law; their strata often lie horizontally, or risetowards the edge of the large dried-up basons, which in America are called Llanos, and inAfricaDeserts. La Condamine says that in Peru and Quito he observedno petrifactions. The cordillera of Quito, however, is notlike that of Parima, naked granite, for at Cuença, and onthe south side, there is gypsum and alluvial chalk. Buffon dwells much, in his Epoques de la Nature, on the questionwhether South America contains petrifactions? I havefound an immense quantity of them in calcareous alluvialsandstone which covers the northern and southern decli-vity of the coast of Venezuola, from the summit of St.Bernandin, and the Altos de Conoma, to the Cerro de Mea-piré, or the headland of Puria and Trinidad. The samestratum is found also in Tobago, Guadaloupe, and St. Do-mingo. An immense quantity of sea and land shells,which in Europe are seldom found mixed together, cellu-lariæ, madrepores, cerallines, and astroites, are found in- |34| terspersed in this sandstone. The shells themselves are halfbroken: whole rocks consist merely of such remains re-duced to powder. My fellow-traveller, Bonpland, discoveredin them shells of the genus Pinna, Venus, and Ostrea, ofwhich living specimens are still met with on that coast; anobservation of great importance to geology. Every thingshows that this stratum, which I have seen only at the di-stance of nine or ten miles from the present coast, is of verymodern origin, and that the fluid in which it was producedhad been in a state of violent motion. The petrified shellsin a much older stratum of compact limestone are scarcerand much differently stratified: they are anomia, terebratu-lites, &c. placed together in families, and in such a mannerthat it is seen that they have lived (as those of MountSalive, the Heinberg near Göttingen, of Jena, and Geneva)on the spot where they are now found petrified. They arenot interspersed throughout the whole mass of the lime-stone; they are only peculiar to certain strata. Many rocksmay be examined without finding any of these petrifactions;but where found they are in great quantity, and presentthemselves chiefly on great heights; peculiarities whichthey have in common with the shells found in the lime-stone of the high Alps of Swisserland and Salzburg, whichis identic with the hardened marl of Thuringia, a limestonewhich lies above the very old sandstone. I must observe also, that, besides the new sandstonestratum with a calcareous base, of which I have alreadyspoken, the petrifactions do not often occur; and I wasparticularly astonished to find no single belemnites or am-monites which are so common in all the mountains ofEurope. The Llano of Orinoco, and that even of RioNegro, are covered with a coarse grained breccia (nagel-fluhe) which contains no petrified shells, and perhaps coversthe other alluvial strata with petrifactions. But this brecciacontains on the other hand petrified trunks of trees, whichare sometimes found of the length of a toise, and of thediameter of two feet. They seem to belong to a kind of Malphigia. The sandstone which contains all kinds of marine ani-mals (the quarry of Punta del Barrigon near Araya is of thissort) never exceeds the height of from 30 to 40 toises. Inseveral places it forms the bottom of the Gulph of Mexico(Cabo Blanco, Punta Araya). In the compact limestone Inever saw petrified shells above the height of 800 toises;but other very new testimonies prove the residence of thewater at much greater heights. Slate found on the Silla de |35| Caracas, at the height of 1130 toises, proves that the wateronce, as on the Bonhomme in Savoy, formed this aperturebetween the two peaks or pyramids of the Avila, an aper-ture which is much older than the five counted in the cor-dillera of the coast, namely, those of Rio Neveri, Unare,Tuy, Mamon, and Guyaca. Among the mountains of theprovince of Cumana, there are very singular valleys of aperfect circular form, which seem to be dried up lakes. Ofthis kind are the valleys of Cumanacoa and St. Augustine,507 toises in depth, which are celebrated for the refreshingcoolness which travellers experience in them. When the modern action of water is considered, two op-posite effects are observed: one recollects a very distantepoch, when the irruption of the sea formed the Gulph ofCariaco and the Golfo Triste; separated Trinidad and Mar-garetha from the main land, and convulsed the coast ofMochima and Santa Fé, where the islands of la Boracha,Picua, and Caracas, form a heap of ruins. The sea thenattacked the land; but the contest did not long continue:the ocean again begins to draw back. The islands Cocheand Cuagua are shoals which emerged from the water; thelarge plain of Salado, lying in Cumana, belongs to the Bayof Cariaco, and is only 5\( \frac{1}{2} \) toises above the level of the sea.The hill on which the castle of St. Antonio is situated wasan island in this gulph, as an arm of the sea passed to thenorth of Tatoraqual through the Charas towards Punta De-legada, as is proved by a multitude of unaltered shells. Itis observed here and at Barcelona that the sea is dailyretiring: in the harbour of Barcelona it has lost in 20 yearsabove 900 toises. Is this decrease of the sea in the Gulphof Mexico general, or is it the case here, as in the Mediter-ranean Sea, that it gains in one point and loses in another?This retreat of the sea must not be confounded with an-other real phænomenon easy to be explained, namely, thedecrease of fresh water, of rain, and of the rivers in thiscontinent. The Orinoco, as we see it at present, is nolonger the shadow of what it was 1000 years ago, accord-ing to the evidence of the traces which the water has lefton both banks at the height of 70 or 80 toises. These traceshave long attracted the notice of learned Europeans whohave seen the Barraguan, the Cueva de Ataruipe (the bury-ing place of the Atures Indians, who formed a kind ofmummies), the Cerro Cuma, the Daminari, the Keri, Oco,and Ouivitari, the bottom of which at present is scarcelycovered by the foam of the Cataracts of Maypuré. Thesetraces remind the Indians of a great inundation, during |36| which many persons saved themselves on rafts of Agave,and afterwards cut out inscriptions and hieroglyphics, withwhich the granite of Urnana, of Incaramada, and the banksof Cassiquiaré, are seen covered, but of which no one atpresent has the key. This tradition, common among theIndians of Erovato and of Parima, shows great analogy withthe mythology of the antients. People think they read thehistory of Deucalion, and Pauw would find the remembranceof this flood not uninteresting. [To be concluded in our next.]
|172|

Sketch of a Geological Delineation of South Ame-rica. By F. A. Von Humboldt.

[Concluded from p. 36.] Having already given a cursory view of the general ap-pearance which the mountains of South America exhibit tothe eye of the geologist, I shall now enumerate the differentkinds of mountains which I have hitherto discovered in thatcountry, beginning with the oldest.

I. Primitive Mountains.

Granite.—The whole cordillera of Parima, and particu-larly the neighbourhood of the volcanoes of Duida and Mar-cielago, consist of granite, which does not form a transitioninto gneiss. In the cordillera of the coast it is almost everywhere covered and mixed with gneiss and micaceous schist.I saw it disposed in strata of from two to three feet in thick-ness, exceedingly regular, declining from three to four perleague, towards the north-west between Valencia and Porto-cabello. I found it on the Rincon del Diablo south-eastfrom Portocabello, with large and beautiful crystals of feld-spar an inch and a half in diameter, like the large grainedgranite on the high summits of the Schneegebirg and theFichtelberg, those of Scotland and Chamouni. It is heresplit into regular prisms; and I saw it on Calavera du Cerrode Mariana beyond Cura, and on the Silla de Caracas,in this prismatic form, which the learned mineralogistM. Karsten observed on the Schneekoppe in Silesia. Thenorthern part of Germany, and the lands on the Baltic inEurope, but not the plain to the south of the Fichtelbergin Swabia and Bavaria, are full of monstrous blocks of gra-nite which have rolled down from the heights. In neitherof the llanos of South America, that of Orinoco, and thatof the Amazon river, did we find any such masses, and nofragments of primitive mountains. The granite mountainsof Los Mariches near Caracas, and those of Torrito be- |173| tween Valencia and St. Carlos, and that of Sierra Nevedade Merida, contain, like that of St. Gothard, fissures whichare covered with very beautiful and large rock crystals. The granite is covered with gneiss and micaceous schist,particularly on the cordillera of the coast of Venezuela.Gneiss is abundant in particular from Cape Chichibocoa toCape Codera in the Tequez, Cocuiza, and the mountain Guigue, as well as in the islands of the Lake of Valencia,where I found (on Cape Blanc, opposite to Guacara,) blackishquartz in the gneiss which passes into Lydian stone, orrather into the schistous state of Werner. The Macanaoon Margaret’s island, and the whole cordillera on the isth-mus of Cariaco, is nothing else than micaceous schist fullof red garnets; and at Maniquarez it is combined with alittle cyanite. Green garnets are intermixed with the gneissof the mountain Avila. In the gneiss of the rock Cala-micari in Cassiquiare, and in the granite of Las Trincherasnear Valencia, I saw round masses, from three to fourinches in diameter, interspersed, which consisted of finergrained granite, yellow feldspar, a great deal of quartz, andscarcely any mica. Is this old granite contained in someof later formation, or are these masses, which have the ap-pearance of accumulations, merely the effect of attraction,which here and there made the particles to approach nearerto each other, but at the same time that the whole moun-tain was formed? This phænomenon of one kind of gra-nite interspersed in the other is observed also in Silesia, atWunsiedel, on the Fichtelberg, in Chamouni, on St. Ber-nard, on the Escurial, and in Galicia. Nature is uniformin her natural productions, even to the small variations inproportions. The micaceous schist passes into talc schist in the cor-dillera of the coast, on the mountain Capaya, and on theQuebrada Secca, in the valley del Tuy. In the cordilleraof Parima talc is found in very large shining masses, andthis has contributed so much to the celebrity of the Do-rado, or Cerro Ucucuamo, between the river Esquivo andMao, in the island Pumacena. The bright fiery appearanceexhibited sometimes by the truncated pyramids of the largeCerro Calitamini, near Cunavami, at sun-setting, seems alsoto proceed from a stratum of talcy schist cut perpendicu-larly towards the west. Small idols of nephrite, which I saw brought from Ero-vato, show that to the south of Raudal de Mura there arenephrite rocks in gneiss like those I found at the bottom ofSt. Gothard, near Ursern. This formation was repeated by |174| nature in the land of the Tupinambaros Indians. La Con-damine discovered this variation of the hard nephrite, whichis known under the name of the Amazon stone. The granite, gneiss, and micaceous schist, contain here,as in Europe, strata of chlorite schist arranged under eachother in the sea at Cape Blanc west from Guayra. Verypure and beautiful hornblend schist is found in the streets ofGuyana; and, still more south, in the cordillera of Parima,feldspar effloresces into porcelain earth in the Silla de Ca-racas; strata of quartz, with magnetic iron-stone, is foundat the sources of the Cutuche, near Caracas; grained folia-ceous, primitive limestone, without tremolite, but with agreat deal of sulphureous pyrites and sparry iron-stone, onthe Quebrada de Topo on the road from Caracas to Guayra.This limestone is entirely wanting in the cordillera of Pa-rima, where it has been sought for many years. Zeichenschist, a kind of carbonaceous iron, and pretty pure gra-phite, are found in the Quebrada de Tocume near Chacao,in the Quebrada Secca near Tuy, and north from the La-guna Chica; on the difficult road which leads across theisthmus of Cariaco to Chiparipara, there are found veinsof quartz, which contain auriferous sulphureous pyritesand antimony, native gold, gray silver ore, mountain blue,malachite, &c. The copper ore of Aroa is the only kind here taken fromthe earth: sixty or seventy slaves obtain yearly 1500 quin-tals at most of refined copper. The quintal is sold fortwelve piastres. The valley in which this ore is dug up isless unhealthful than the valleys near the sea where theIndians wash gold; namely, Urama, Maron, and Alpago-ton, where the air appears to be poisonous, as is the casein the fertile valley of Cararinas between Nirgua and RioJaracuy. The gold is dispersed throughout the whole pro-vince, particularly in the strata of quartz at Baruta, Catia, Guigue, Quebrada del Oro near Tuy, and on the Cerro deChacao, and Real de Santa Barbara near St. John, whereI found barytic spar, the only instance I ever met with inthis country. All the rivers of the province of Characas,wash down gold. It however does not thence follow thatthis province is rich, and contains veins of gold not yetdiscovered: the gold may be interspersed in whole massesof granite; and I am acquainted with no high granite cor-dillera, either here or in Europe, the rivers of which donot wash down gold. The Cerro Duida of Esmeralda inDorado, the Quebrada du Tigre near Encaramada, and theCerros de Amoco, the Real de S. Barbaro near St. John, |175| the Quebrada de Catia, the alum ore of Chuparuparu, sometraces of iron ore in the llano of St. Sebastian, and par-ticularly the Aroa abundant in copper, seem to call for theindustry of the miners. Argillaceous schist is very scarce: it covers the micace-ous schist on the southern declivity of Venezuela, in theneighbourhood of the Llanos, in the Quebradas de Malparo,and Piedra Azul: there is blue argillaceous schist, withveins of quartz, on the isthmus of Cariaco, near Chupa-ruparu, in the Distillador Arroyo du Robola, and also onMacanao. In the four last-mentioned places there arefound in the argillaceous schist alum and vitriolic schist, instrata of two or three feet in thickness, which efflorescesulphate of alumine, or natural alum, with which the Indi-ans of Guayqueries carry on a little trade. Serpentine is found on the cordillera of Venezuela abovemicaceous schist, on the surface of Villa de Cura, at theheight of 245 toises; between the Cerro de Piedras Negrasand the Rio Tucutunemo, here and there green olivin mixedwith glimmer, without garnets, schillerspath, or hornblend,but with veins of bluish lardstone. Grunstein (green rock), original trapp, an intimate unionof hornblend and feldspar, sometimes intermixed with sul-phureous pyrites and quartz, often confounded with ba-saltes, and very little known in Europe, is found in strataof two fathoms in thickness, or balls of from three to fourfeet in diameter, composed of concentric strata united withmicaceous schist or original argillaceous schist, in severalplaces of the northern and southern declivity of the cordil-lera of the mountain Avila, in the sea near Cape Blanc, ina real vein which traverses the strata of gneiss, but inter-mixed with newer granite, which fills up the vein between Antimano and Carapa near Caracas. The gray stone con-tains here red garnets which I have never seen in Europe.I have sent specimens of them to Madrid in the first boxwhich I transmitted to the captain-general of Caracas.

II. Kind of Mountains which form the Transition fromPrimitive to Alluvial Mountains. Formation of theTransition of Werner.

This formation is found in particular to the north of theParima cordillera, opposite to Caccara, and in large masseson the southern declivity of the Venezuela cordillera. Be-tween the llanos and Morros of S. Juan, between the Villade Gura and Parapara, between longitude 9° 33′ and 9° 55′,one seems to enter a land of basaltes, on descending from |176| the height of 300 to 63 toises above the level of the sea.Every thing reminds one here of the mountains of Bilinin Bohemia, or of Vienza in Italy. The primitive ser-pentin on the banks of the Tucutunemo, which like that ofSilesia contains copper veins, becomes gradually mixedwith feldspar and hornblend, and makes the transition intotrapp or grunstein. This trapp is found in stratified massesdeclining 70° towards the north, or in balls with concen-tric strata, which, interspersed in calcareous clay, formpyramidal hills; sometimes the transition argillaceousschist of Werner is interspersed in green and very heavyargillaceous schist, which consists of hornblend and argil-laceous schist intimately mixed together. The same argil-laceous schist makes a transition near the Quebrada dePiedras Azules into the primitive argillaceous schist abovewhich it lies. The trapp or grunstein contains also foliace-ous olivin, crystallized in pyramids of four faces, a fossilwhich M. Friesleben discovered on our tour into Bohemia,and deseribed in the Mineralogical Journal of Freyberg,augite with a shelly fracture, leucite in dodecaedra, thesides of the holes and cavities of which are covered withgreen earth like that of Verona, and a substance whichhas the splendour of mother-of-pearl, and which I consi-der as zeolite. All these interspersed fossils increase to-wards Parapara, and the trapp there forms real amygdalite.Above this amygdalite, near the hill Florez, at the entranceinto the large valley of Orinoco, lies that remarkable stonewhich is scarce in Europe, and which Werner describesunder the name of porphyry schist. The hornschist of Charpentier, a kind of rock which accompanies basaltes,forms groups of irregular columns, and by the impressionof the ferns which it contains in the middle of the moun-tains, as discovered by M. Reuss, proves that it is not ofvolcanic origin. The porphyry schist of Parapara is a greenmass of sonorous stone, which is very hard, acute angled,and has transparent fragments on the edges: it strikes firewith steel, and contains vitreous feldspar. I did not ex-pect to find this stone again in South America; it howeverdoes not form here such groups of grotesque appearance asin Bohemia, and on mount Eugoneide in the Venetian ter-ritories, where I have seen it.

III. Alluvial Mountains.

These secondary formations, which are of later originthan the organic bodies of the earth, follow each other inthe order of their relative age, as in the plains of Europe, |177| and as has been mentioned by that excellent geologist M. Von Buch, in his Mineralogical Description of the Countyof Glatz in Silesia, a small work, which contains valuableideas and interesting observations. I found here two formations of compact limestone. Theone makes a transition into the small grained and imper-ceptibly foliaceous limestone, and is identic with the lime-stone of the high Alps; the other is compact, exceedinglyhomogeneous, with several petrifactions of shells, and ana-logous to the limestone of Jura, Pappenheim, Gibraltar,Verona, Dalmatia, and Suez; a formation of foliaceousgypsum, and another mixed with clay, containing commonsalt and rock oil. The saline clay which I always foundaccompanied with rock salt in the Tyrol, Steyermark, andSalzbourg in Swisserland; marl schist stratified in lime-stone of the Alps, and two formations of sandstone, oneof which is older and almost without petrifactions, some-times small and large-grained sandstone of the llanos, andthe other full of the remains of marine animals, whichforms the transition into the compact limestone. The blue limestone of the Alps, with white veins of cal-careous spar, is found on the micaceous schist lying uponthe Quebrada Secca near Tuy to the east from the PuntaDelgada, on the road from Cumana, on the Impossibletowards Bordones, on the island of Trinidad, and on themountain Paria. This limestone contains here, as in Swis-serland, three formations arranged under each other:—1st, Repeated strata of black marl schist; marl schist, orcupreous schist of Thuringia, mixed with pyrites, and earthpitch on the Cuchivana near Cumanacoa. This clay con-tains carbon, and absorbs the oxygen of the atmosphericair. 2d, Saline clay mixed with rock salt and crystallizedgypsum, in which the salt pits of Araga, Pozuelas, andMargaret’s Island are placed. 3d, Small-grained sand-stone, with a calcareous base, almost without petrifactionsof shells, always penetrated by water, and sometimes withbrown strata of ferruginous earth on the Cocollard, Tamir-quiri. I am not certain whether the last-mentioned stonelies on the limestone, or is not sometimes covered by it. This limestone serves as the base for a newer one. It isexceedingly white and compact, full of holes (Cueva delGuacharo, in which thousands of birds reside, and amongwhich is a new genus of Caprimulgus, from which a kindof fat much used in the country is obtained, Cueva delS. Juan, Cueva del Cuchivano); sometimes porous likethe Franconian, and forms grotesque rocks (Morros de |178| S. Juan, de S. Sebastian). It contains strata of blackhornstone, which passes into siliceous schist or Lydianstone (Morro de Barcelona) and Egyptian jasper to thesouth of Curataquiche. Over this compact limestone isplaced, as on Jura, very beautiful alabaster in large massesat Soro, in Golfo Triste. All this gypsum contains sulphuras well as the gypsum of Bex and Kretzetzow, and in theCarpathians. This formation of limestone, with blackhornstone and gypsum, seems also to occur in the valleyof the Amazon and Rio Negro, where they were found by la Condamine near Cuença, between Racam and Guyausi,on the east side of the Andes. This limestone and gypsum (the latter in the llano ofBarcelona near Cachipé) are often covered in the valleys ofOrinoco, and the Amazon river, by a conglomeration orsandstone, with large strata, in which the remains of lime-stone, quartz, Lydian stone, all of greater antiquity thanthe sandstone itself, occur. This conglomeration, breccia,which has a similarity to that of Aranjuez, Salzburg, &c.,is extended over more than 18000 square miles in thellanos. It contains strata with small grains and traces ofbrown and red iron ore. I have never seen petrifactionsin it. The sandstone full of shells and coral, without any tracesof crocodiles in a country which unfortunately contains somany, and which passes into limestone, but on closer ex-amination is intermixed with grains of quartz, is of newerformation, and always nearer the coasts: P. Araya, CaboBlanco, Castillo, S. Antonio de Cumana. It may perhaps be expected that I should close this de-scription with an enumeration of the volcanie productionsof this country, which has been convulsed by the mostterrible earthquakes, the high summits of which (Duida),and lately some of its caverns (Cueva du Cuchivano), vomitforth flames, where boiling springs are thrown up fromGolfo Triste to the Sierra Nevada de Merida (the springsof Triachevar I found to be 72°·3 of Reaumur), where, onthe coast of Paria, near Cumacator, there is an air volcano,the noise of which is heard at a great distance, and sul-phureous pits in several places as at Guadaloupe—a coun-try where, in the extent of several square miles, the wholesurface is undermined and hollow (Tierra Hueca de Cari-aco), where, in the year 1766, the earth, after being agi-tated eleven months by violent shocks, opened on all sides,and poured forth sulphureous water and bitumen; andwhere, in the midst of the driest plains in the Mera de |179| Guanipa and du Cary, flames burst from the earth. Butnature discharges me from this task. The effects ofthe volcanoes in this part of the world are very differentfrom those seen in Europe. Great and melancholy in theirconsequences, they change the rocks which are exposed totheir action. The immense revolution of Pelileo and Ton-guragua de Zuito has not only covered the earth withlava, but with clayey mud, deposited by the sulphureouswater which spouted from the earth. The sulphureousgypsum, the mixture of sulphureous pyrites in all therocks, even in granite, the bituminous saline clay, therock oil, or asphaltum, which every where floats on the wateror lies on the ground, the immeasurable quantity of rain-water, and the lakes which penetrate into the earth heatedby the sun, the aqueous vapours and immense quantities ofhydrogen gas every where disengaged, seem to be the prin-cipal causes which contribute to produce these volcaniceffects. The sulphureous pits of Guadaloupe, of Montmisene,St. Christopher de l’Oualiban, St. Lucia, and Montserrat,are in all probability connected with those on the coast ofParia. These volcanoes, however, belong rather to the pro-vince of natural philosophy than of mineralogy; and I mustvisit other countries before I can venture to form any opi-nion on so difficult a subject. May Heaven avert from theeastern side of New Andalusia such a catastrophe as thatwhich has convulsed the plains of Pelileo!

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