RECORD: Darwin, C. R. Geological diary: Chili. (2-6.1835) CUL-DAR36.447-451 Transcribed by Kees Rookmaaker, edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Kees Rookmaaker, corrected and edited by John van Wyhe 9.2011. RN2

NOTE: This document, part of the largest scientific document composed by Darwin during the voyage of the Beagle, is written mostly in ink. Where pencil was used instead this is noted in the textual notes. Marginal notes are here integrated into the text. This document continues from page 443. See the Beagle Diary pp. 553 and following.

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Reproduced with the permission of the Syndics of Cambridge University Library and William Huxley Darwin.

See the introduction to the Geological Diary by Gordon Chancellor.


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often emits much fine ashes. — At time of eruption enormous volcanic bombs can be seen from S. Carlos a distance of 93 miles, which at night assume all forms, at night ejected upwards. — They appear to burst in the air, & are said to resemble enormous trees & other forms. — The summit is firmed by a very sharp. peak, the crater by description must be lower down & on one side. (a) — 51 & 1/2 miles South of this we have a four 3 peaked mountain called Mellamoy; said by some Chilotans to be a volcano. — Regular cone slope of side 25°. — height (not known ft. — The latitude of this mountain is 44° 1' 30" S. —

(a) Is it same latitude with volcano of [Clements] in Arrowsmith map1

From oral testimony I can hear of no other volcano further South. — We have however seen volcanic products. And there is one very conical peak at no great distance. — In Bulkeley & Cummings Narrative they mention having experienced a severe shock when South of C. Tres Montes. — I have never heard of one in T. del Fuego. — It may also be remarked, as before, that in front of the last four volcanos, there is a comparative absence of subordinate chains: as if the force

Ascertain date may be coincident with some bad shock

August 25th 1741

(B)

1 Arrowsmith 1823.

447 verso

(a) All the conge measurements angular & taken by the officers. — Between Corcobado & Mellamoy there is a four peaked mountain Yantetes, 7425 ? — or 6725.

Those the four principal mountains in this part of Cordilleras (all capped with perpetual snow, do not reach the height of 8000 ft. — The mean height of the ridge must therefore be trifling. —

All the volcanos are placed near the sea & in direct N & S line. —

On the 26th of January 1835 (& after a week unusually fine weather) the height of perpetual snow of the Corcobado (Lat 43° — 11') was (4103 ft). — The line was very distinct. Mr King took with pocket sextant the ∠r from the peak to this line: calculated it & substituted the result from the total height. —

On Feby 2d [1835] from our anchorage at P. Arena, S. Carlos, the angle from peak to snow line was 20' in the mountain South of Osorno (lat. 41°. 20'). — Subtract this from total height. —

(B) Does not the transverse chain in Mexico with 5 volcanos run out of plain without other subordinate ranges? —

Is it so in the narrow parts of Panama, in Guatamala where here are so many volcanos? — Around [Chinaborro] & Pichincha &c are there not elevated plains? — Must we not then conclude that volcanic eruptions & upheaval of secondary ranges are efforts which replace each other?

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necessary to raise these had been expanded in the greater number of vents. — I may here remark, that the pumice must be a very general product of all these volcanos, for the fact that such has been found on the plains of R. Blanco, R. Colorado, Negro & Chinpeta & Portillo on the East side of Cordilleras. — on the West in the Plain of St Jago. S. Fernando. — (Copiapo) Isd of Mocha & Chiloe. —

I have a few for words on the subject of earthquakes. — From several enquiries it appears certain, that earthquakes are not so severely felt on whole Eastern side, as on the West. — Likewise the shocks at seaports of Chili are much severer than in the inland towns of Aconcagua, St Jago &c &c. — From the motion of the ground &c the people at large think the shocks generally come from seaward. — At Concepcion, on (Feb 20th) all thought the movement came from SW: — At Valparaiso in 22 some thought it came from seaward & North, others seaward & South. — I believe the direction (a) can oftener be distinguished, than which of the two points. — at 22 the motion must

448 verso

(a) In 1822. The water is said to have come in from the North, black as ink & the whole surface of the Bay to have boiled with the emission of gas. — This little fact must frequently be caused by the substance of the mud. —

At Lima a chain of large bubbles showed the line of our chain anchor during mooring ship. —

In Marsden's Sumatra1 it is said that houses on land much least affected!

Earthquakes on coast do not always affect volcanos. —

1 Marsden 1811.

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The remarkable fact of the last earthquake of Concepcion being connected with an eruption & extreme movement at Juan Fernandez, an island 400? miles distant & remote from the land, whilst in the same latitude at Valparaiso, it was nothing of consequence; becomes still more remarkable, when it is known, that the same coincidence happened in the famous earthquake of 51. — The above facts would incline one to the believe, that the movement generally was connected with the disturbances in the bed of the Pacific: this first impression is to think the Andes, the great chain with volcanos, is the axis. — so no doubt it is in some parts as in Chiloe. — May we connect the universal fact of the West side of Andes being fringed with subordinate (or many posterior) lines of elevation with the present greater frequency & force of earthquake on the side of the Pacifick. —

I cannot forbear pointing out one other coincidence. — Perhaps no place on coast of S. America has suffered so much from earthquakes as Concepcion. Now it is certain, that I have no where seen the tertiary strata so much (indeed in few other places at all) distracted by

449 verso [blank]

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subterranean movements (a). — I confess I saw all these very violent earthquakes as caused by line of elevation at the bottom of the Pacifick, which as in the case of Juan Fernandez are probably oftentimes connected with volcanic eruptions. —

For some months previous to the great earthquake of Concepcion, there appears to have been a remarkable (perhaps more than accidentally connected in time by tendency to subterranean violence in different & distant parts of S. America the Cordilleras. — at Rialeja, from morning of Jan 20th to 23d there was a tremendous eruption, the air sky for a long time being blackened (B), with ashes. —

In a New Orleans paper dated Feb. 7th, there is a letter from Omon giving an account of several towns being demolished & 5 volcanos having burst out near Truxillo. — Was it not December that S. Martha was overthrown with such destruction of human life? — On Jan 19th (1835) we saw from the Beagle anchored at S. Carlos. the at midnight the volcano of Osorno in violent action. Some months subsequently Mr Byerbache, a merchant in Valparaiso told me, that being on board a vessel, the Captain awoke him late in the night to see the volcano of Aconcagua in action. —

1 Byerbache has not been identified.

450 verso

(a). I do not know whether Mr Caldcleugh has following facts in his papers: a long narrow lake which runs nearly E & W, South of S. Fernando has a wave caused in its waters of nearly a yard high. —

That the irrigatory streams which flowed to the West were checked in their course for a short period. — Mr Smith. —

(B) This eruption was came from the Cerro of Cosiguina, which is near the towns Choluleja Racaoma Viego. The accompanying earthquakes do not appear to have been excessively violent. The quantity of volcanic ashes astounding. — Valparaiso. Papas (clearly no doubt the letter from Onera refers to the same event, it there however states that 5 volcanos burst out & towns subsided. This will be worth enquiring about. It will be seen the first noises & empt were heard very early in the morning & the cloud of ashes were seen at daylight of the morning of the 20th of January. There was an improbability that two volcanos, one of which is so seldom active should have burst out on the same house — Note that a thread without some physical connection is added the house that a thread is added, the improbability of chance is excessive. — Yet these 2 extreme volcanos are 53° of latitude apart. — Who can say how many intermediate volcanos besides Aconcagua were in activity? — It would be worth looking at Quito, Cumana, Vacaceras, Cuba. & St Fe, Bogota papers. — There was an earthquake about that time or earlier in the West indies — in Jamaica. — a general period of volcanic energy seems common before ant great commotion. — Caracias & [illeg]

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This time is interesting, as it is of such rare occurrence that many travellers have doubted whether this peak, which is 2300 ft high, is a volcano. This eruption took place took place at night on the 19th of Jany, the very same night as we saw Osorno, 600 miles distant, in activity. I only discovered this by referring to my Journal (a).

Was this most curious coincidence accidental: — Or has the one volcanic power acted at these two remote points stretching across that basin, which a month subsequently at Concepcion was so violently agitated. — And Whilst at this latter period. neither Aconcagua nor Villa Rica a volcano much closer to the scene of action were agitated. —

All over Chili, where certainly inhabitants have excellent opportunity of judging that connection of earthquake & state of weather, is most firmly believed in by the natives & most of the old residents. — This is most conspicuous in the North of Chili, where the climate is very regular & so little rain falls. — A smart earthquake if not immediately followed by rain, is by heavy, dull cloudy weather: if nature was trying to produce a shower. I do not here refer to those devastating shocks, but others of a much less severe nature.

451 verso

(a) I may here remark, how little attention such facts excite in these countries. — I met no one scarcely any who knew that Aconcagua has been in action at Valparaiso. At Chiloe it is my belief of the few, who at that time heard or saw Osorno at this time would even recollect the month in which the eruption alluded to happened. — The coincidence by me only was discovered by reference to my Journal. —

I should have stated that in neither place, the eruptions appeared to have been accompanied by earthquakes.

Humboldt II p 225.1 — states "The earthquake of Cumana are connected with those of the W. India isds; & it has even been suspected, that they have some connection with the volcanic phenomena of the Cordilleras of the Andes."

This chiefly rests on the period of great subterranean commotion happening nearly at same periods at Quito, Leaward Isd (& Guadaloupe is eruption) & Cumana. This distance equals about 1650 miles. — From Rialeja to Osorno 53 degrees of latitude = 3180 miles! —

1 Humboldt 1819-1829, vol. 2, p. 225.


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