HYPSOMETRIC ADDENDA.

I am indebted to Mr. Pentland (whose scientific labours have thrown so much light on the geology and geography of Bolivia) for the following determinations, which he communicated to me in a letter written from Paris, in October 1848, after the publication of his great map:—

Nevado of Sorata, or Ancohuma. S. lat. Long. from Greenwich. Height in English Feet.

South Peak 15° 51′ 33″ 68° 33′ 55″ 21286

North Peak 15° 49′ 18″ 68° 33′ 52″ 21043

Illimani.

South Peak 16° 38′ 52″ 67° 49′ 18″ 21145

Middle Peak 16° 38′ 26″ 67° 49′ 17″ 21094

North Peak 16° 37′ 50″ 67° 49′ 39″ 21060

The heights (with the exception of the unimportant difference of a few feet in the South Peak of Illimani) are the same as those given in the map of the Lake of Titicaca. A sketch of the last-named mountain (Illimani), as it shews itself in all its majesty from La Paz, has been given by Mr. Pentland in the Journal of the Royal Geographical Society, Vol. V. (1835), p. 77. This was five years after the publication of the first measurements in the Annuaire du Bureau des Longitudes for 1830, p. 323, which results I myself hastened to make known in Germany. (Hertha, Zeitschrift für Erd und Völkerkunde, von Berghaus, Bd. xiii. 1829, S. 3–29.) The Nevado de Sorata is to the east of the village Sorata, or Esquibel: it is called in the Ymarra language, according to Pentland, Ancomani, Itampu, and Illhampu. We recognise in “Illimani,” the Ymarra word “illi,” snow.

If, however, in the eastern chain of Bolivia the Sorata was long assumed 3718 French, or 3952 English feet, and the Illimani 2675 French, or 2851 English, feet too high, there are in the western chain of the same country, according to Pentland’s map of Titicaca (1848), four peaks to the east of Arica and between lat. 18° 7′ and 18° 25′, all of which are higher than Chimborazo, which is 21422 English or 20100 French feet. These four peaks are—

Pomarape 21700 English feet, or 20360 French feet.

Gualateiri 21960 „ „ 20604 „ „

Parinacota 22030 „ „ 20670 „ „

Sahama 22350 „ „ 20971 „ „

Berghaus has applied to the eastern and western chains of the Andes of Bolivia the investigation published by me in the Annales des Sciences Naturelles, T. iv. 1825, p. 225–253, of the proportion (very different in different mountain chains), which the general height of the ridge, the crest, or kamm (the mean height of the passes), bears to the highest summits or culminating points. He finds, following Pentland’s map, the mean height of the passes in the eastern chain 12672 French, or 13502 English feet; and in the western chain 13602 French, or 14896 English feet. The culminating points are 19972 and 20971 French, 21286 and 22350 English feet; consequently the ratio of the height of the ridge to that of the culminating point is, in the eastern chain, as 1 : 1.57, and in the western chain as 1 : 1.54. (Berghaus, Zeitschrift für Erdkunde, Band. ix. S. 322–326). This ratio, which is, as it were, the measure of the subterranean elevating force, is very similar to that which exists in the Pyrenees, but very different from the Alps, where the mean height of the passes is less as compared with Mont Blanc. The ratios are, in the Pyrenees, = 1 : 1.43, and in the Alps, = 1 : 2.09.

But, according to Fitz Roy and Darwin, the height of the Sahama is still surpassed by 796 French, or 850 English feet, by that of the volcano of Aconcagua, on the north east of Valparaiso, in Chili, in S. lat. 32° 39′. The officers of the Adventure and Beagle, in Fitz Roy’s Expedition, found, in August 1835, the summit of Acongagua between 23000 and 23400 English feet. If we take it at 23200 (equal to 21767 Paris feet), this volcano would be 1667 French, or 1777 English, feet higher than the Chimborazo. (Fitz Roy, Voyages of the Adventure and Beagle, 1839, Vol. ii. p. 481; Darwin, Journal of Researches, 1845, pp. 223 and 291.) According to more recent calculations, the height of Acongagua is given as 22431 French, or 23907 English feet. (Mary Somerville, Physical Geogr. 1849, Vol. ii. p. 425.)

Our knowledge of the systems of mountains which, north of the parallels of 30° and 31° N. lat., are called the Rocky Mountains and the Sierra Nevada of California, has received most important additions, geologically, botanically, hypsometrically, and geographically by astronomical determinations of position, from the excellent works of Charles Frémont (Geographical Memoir upon Upper California, an illustration of his Map of Oregon and California, 1848); of Dr. Wislizenus (Memoir of a Tour to Northern Mexico, connected with Col. Doniphan’s Expedition, 1848); and of Lieutenants Abert and Peck (Expedition on the Upper Arkansas, 1845; and Examination of New Mexico in 1846 and 1847.) There prevails throughout these different North American works a true scientific spirit, which is deserving of the greatest commendation. The remarkable elevated plain, which rises to an uninterrupted height of four or five thousand French (4260 and 5330 English) feet, between the Rocky Mountains and the Sierra Nevada of California, of which I have spoken in p. 44, and which is called the Great Basin, forms an inland closed river basin, and has hot springs and salt lakes. None of its rivers,—Bear River, Carson River, and Humboldt River,—find their way to the sea. The Lake, which I was led by combinations and inferences to represent, in the great Map of Mexico drawn by me in 1804, under the name of Lake Timpanogos, is the great Salt Lake of Frémont’s Map: it is sixty geographical miles long from north to south, and ten broad; and it communicates with the fresh water lake of Utah, which is situated at a higher level, and receives the Timpanogos or Timpanaozu River, which enters it from the eastward, in lat. 40° 13′. The circumstance of the Timpanogos Lake of my map not having been placed by me sufficiently far to the north and west, is to be attributed to the entire want, at that time, of any astronomical determinations of the position of Santa Fé, in New Mexico. The error amounts, for the western margin of the lake, to almost 50 minutes of arc; a difference of absolute longitude which will appear less surprising, if it is remembered that my itinerary map of Guanaxuato could only be based for 15 degrees of latitude on compass surveys, or compass directions, for which I was indebted to Don Pedro de Rivera. (Humboldt, Essai polit. sur la Nouvelle Espagne, T. i. pp. 127–136.) These directions being differently combined by my early deceased fellow-labourer, Herr Friesen, and myself, gave him as the result of his combinations 107° 58′ from Paris as the longitude of Santa Fé, and to me as the result of mine, 107° 13′. According to actual astronomical determinations since obtained, the true longitude appears to be 108° 22′ W. of Paris, or 106° 00′ W. of Greenwich. The relative position of the beds of fossil salt—found in “thick strata of red clay,” on the south east of the island-studded Great Salt Lake (my Laguna de Timpanogos), and not far from the present Fort Mormon and the Utah Lake—was given with perfect correctness in my large map of Mexico. I may refer on this point to the latest evidence of the traveller who made the first well-assured determinations of geographical position in that district:—“The mineral or rock salt, of which a specimen is placed in Congress Library, was found in the place marked by Humboldt in his map of New Spain (northern half), as derived from the journal of the missionary Father Escalante, who attempted (1777) to penetrate the unknown country from Santa Fé of New Mexico to Monterey of the Pacific Ocean. South-east of the Lake Timpanogos is the chain of the Wha-satch Mountains; and in this, at the place where Humboldt has written Montagnes de sel gemme, this mineral is found.” (Frémont, Geogr. Mem. of Upper California, 1848, pp. 8 and 67; compare Humboldt, Essai politique, T. ii. p. 261.)

A great historical interest attaches to this part of the highland, and more particularly to the country round the Lake of Timpanogos, which is perhaps the same with the Lake of Teguayo, the ancestral seat of the Aztecs. In their migration from Aztlan to Tula, and to the Valley of Tenochtitlan (Mexico), this people made three halting places or stations, at which the ruins of the Casas grandes are still to be seen. The first sojourn of the Aztecs was at the Lake of Teguayo, the second on the Rio Gila, and the third not far from the Presidio de Llanos. Lieutenant Abert found on the banks of the Gila the same immense number of fragments of pottery ornamented with painting, and scattered over a considerable tract of ground, which had astonished the missionaries Francisco Garces and Pedro Fonte in that locality. These remains of the products of human skill are supposed to indicate the existence of a former higher civilisation in these now solitary regions. Remains of buildings in the singular style of architecture of the Aztecs, and of their houses of seven stories, are also found far to the eastward of the Rio Grande del Norte; for example, in Taos. (Compare Abert’s Examination of New Mexico, in the Documents of Congress, No. 41, pp. 489 and 581–605, with my Essai pol. T. ii. pp. 241–244.) The Sierra Nevada of California is parallel to the Coast of the Pacific; but between the latitudes of 34° and 41°, between San Buenaventura and the Bay of Trinidad, there runs, on the West of the Sierra Nevada, another (smaller) coast chain, of which Monte del Diablo, 3448 French, 3674 English feet high, is the culminating point. In the narrow valley, between this coast chain and the great Sierra Nevada, flow from the south the Rio de San Joaquin, and from the north the Rio del Sacramento, on the banks of which, in rich alluvial soil, are the rich gold-washings now so much resorted to.

I have already referred, p. 43, to a hypsometric levelling, and to barometric measurements made from the junction of the Kanzas River with the Missouri to the Pacific, or throughout the immense extent of 28 degrees of longitude. Dr. Wislizenus has now successfully continued the levelling began by me from the city of Mexico, in the Equinoctial Zone, to the North as far as Santa Fé del Nuevo Mexico, in lat. 35° 38′. It will be seen, perhaps, with surprise, that the elevated plain which forms the broad crest of the Mexican Andes is far from sinking down, as had long been supposed, to an inconsiderable height. I give here for the first time, according to the measurements which we at present possess, the elevations of several points, forming a line of levelling from the city of Mexico to Santa Fé, which latter town is less than four German (sixteen English) geographical miles from the Rio del Norte.

French Feet. Eng. Feet. Observer.

Mexico 7008 7490 Ht.

Tula 6318 6733 Ht.

San Juan del Rio 6090 6490 Ht.

Queretaro 5970 6363 Ht.

Celaya 5646 6017 Ht.

Salamanca 5406 5761 Ht.

Guanaxuato 6414 6836 Ht.

Silao 5546 5910 Br.

Villa de Leon 5755 6133 Br.

Lagos 5983 6376 Br.

Aguas Calientes 5875 6261 Br.

San Luis Potosi 5714 6090 Br.

Zacatecas 7544 8040 Br.

Fresnillo 6797 7244 Br.

Durango 6426 6848 (Oteiza)

Parras 4678 4985 Ws.

Saltillo 4917 5240 Ws.

El Bolson de Mapimi 3600 to 4200 3837 to 4476 Ws.

Chihuahua 4352 4638 Ws.

Cosiquiariachi 5886 6273 Ws.

Passo del Norte, on the Rio Grande del Norte 3557 3812 Ws.

Santa Fé del Nuevo Mexico 6612 7047 Ws.

The letters Ws., Br., and Ht., are placed to distinguish the barometric measurements of Dr. Wislizenus, Oberbergrath Burkart, and my own. Wislizenus has appended to his valuable memoir three vertical sections of the surface of the ground: one from Santa Fé to Chihuahua by Passo del Norte; one from Chihuahua to Reynosa by Parras; and one from Fort Independence (a little to the east of the Confluence of the Missouri and the Kanzas River) to Santa Fé. The calculation is founded on daily corresponding observations of the barometer, made by Engelmann at St. Louis, and by Lilly at New Orleans. If we consider that the difference of latitude between Santa Fé and Mexico is 16° and that thus (apart from deviations from a straight line) the distance in the north and south direction is above 960 geographical miles, we are led to inquire whether there be in any other part of the whole globe a similar conformation of the Earth, equal in extent and elevation (between 5000 and 7000 French, or 5330 and 7460 English feet above the level of the sea) to the highland of which I have just given the levelling, and yet over which four-wheeled waggons can travel as they do from Mexico to Santa Fé. It is formed by the broad, undulating, flattened crest of the chain of the Mexican Andes, and is not the swelling of a valley between two mountain chains, as is the case in some other remarkable elevations of plain or undulating surface—in the Northern Hemisphere, in the “Great Basin” between the Rocky Mountains and the Sierra Nevada of California,—in the Southern Hemisphere, in the high plain of the lake of Titicaca, between the eastern and western chains of the Andes of Bolivia,—and in Asia, in the highlands of Thibet, between the Himalaya and the Kuen-lün.