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Feb. 1835:—

The position of the bones of Mastodon (?)¹ at Port St Julian is of interest, in as much as being subsequent to the remodelling into step of what at first most especially appear the grand (so called) diluvial covering of Patagonia.— It is almost certain that the animal existed subsequently to the shells, which now are found on the coast. I say certain because the 250 and 350 &c plains must have been elevated into dry lands when these bones were covered up & on both these plains abundant shells are found. We hence are limited in any conjectures respecting any great change of climate to account for its former subsistence & its present extirpation.
In regard to the latter of these facts destruction of the former large quadrupeds, the supposition of a diluvial debacle seems beautifully adapted to its explanation; in this case, however, if we limit ourselves to one such destructive flood, it will be better to retain it for the original spreading out of the Porphyry pebbles from the Andes. I have reasons to suppose that this was anterior— not only to this group of bones but also to the immense numbers buried in the Pampas.— The arguments are drawn from the connection of the Tosca rock & matrix of the gravel at R. Negro; also the height of the plains.

¹ The bones were later identified by Richard Owen as Macrauchenia patachonica in Mammalia, pp. 35-56 and plates VIII-XV. Darwin seems to have added the question mark at a later date.

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(a) It may well be expected if the remains large quadrupeds found in so many places in the Americas were overwhelmed by Debacles, with their bones, immense quantities of trees (& stones, if such existed) would be found.— This is not the case in S. America as far as I have seen.—

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With respect then to the death the of species of Terrestrial Mammalia in the S. part of S. America. I am strongly inclined to reject the action of any sudden debacle.— Indeed the very numbers of the remains render it to me more probable that they are owing to a succession of deaths, after the ordinary course of nature.— as M^r Lyell supposed Species may perish as well as individuals; to the arguments he adduces. I hope the Cavia of B. Blanca will be one more small instance of at least a relation of certain genera with certain districts of the earth. This correlation to my mind renders the gradual birth & death of species¹ more probable. The large quadruped of St. Julian lived probably when the land was from 100 to 200 ft lower than at present. If my belief (it will hardly be granted by those who have not seen the plains of Patagonia) that the elevations of the whole coast have every where acted with remarkable equality of force; This same lowering will submerge the Pampas where so many bones are found & afford a weak presumption that the animals to which these remains are found. belong lived at same times.— This reasoning will also include

(a). The following analogy I am aware is a false one; but when I consider the enormous extension of life of an individual plant, seen in the grafting of an Apple tree. & that all these thousand trees are subject to the duration of life which one bud contained. I cannot see much difficulty in believing a similar duration might be propagated with true generation.— If gradual deaths the existence of species is allowed, each according to its kind, we must suppose deaths to follow one after at different epochs, & then successive births must repeople the globe or the number of its inhabitants has varied exceeding at different periods.— A fact supposition in contradiction to the fitness wit which the Author of Nature has now established.—

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the bones of found by Humboldt in plains of Orinoco.— (V my index)

Is the animal of St Julian a Mastodon? Even if a change of climate could be granted it is scarcely possible to believe the plains of gravel ever could have supported a much more luxuriant vegetation
We must suppose like the Camel of Eastern climes or the Guanaco which now lives here, that it was fitted for a stunted vegetation.— Yet their whole genus is furnished with a short neck.— If a rapid river ever flowed out this bay the Carcase might have travelled from the slope of the Andes.—

The latitude 49°-50° is certainly high, (corresponding to North of France & to Germany in Northern Hemisphere) We must remember for a large quadruped of this <bottom of page and c. 2 or 3 lines excised>

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Reflection: on P. Buckland beautiful paper on the fossil remains of large Quadrupeds in NW Coast of America.— Appendix to Beechey¹

In Southern part of S. America. We have seen in the recent period that the E & W coast have been elevated some hundred feet.— I can give very slight reason for the same fact in Basin of Oronoco & in Mexico.— M^r Conrad has proved the same thing in the United States.² Is it not almost probable that the NW Coast has shared this grand & general elevation?— In Tierra del Fuego there are extensive depositions (of the recent period) composed of precisely similar materials as described in NW Coast & called diluvium. but which then is go reason to believe is an ordinary deposition. At Chiloe we see from this structure ([sketch]) that the diluvial matter (mud & variably sized & shaped fragments) has clearly been deposited at distinct periods.— We know at least that they all are a marine deposition & elevated in the recent period.— Again in the Pampas La Plata & Patagonia we know the bones of large Quadrupeds have been generally (if not all) been buried in sediment formed beneath a sea or estuary. With these

¹ Beechey 1831, vol. 2.

² Conrad 1835.

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considerations in mind it is not odd that I am inclined to believe the low cliffs, which line fring a long extent of coast, & which are composed of black mud with angular & rounded pebbles of rock both present & not known there to exist (the same thing occurs abundantly in Chiloe) & which contain numerous large bones (& these latter penetrated by Gypsum) that these cliffs are an ordinary deposit, like those I have adduced & elevated at the same period.
With this we must almost suppose some change of climate has taken place, but not necessarily suddenly to account for their former subsistence.— For their extermination & the materials of the cliffs.

I do not see the necessity of a diluvial debacle.— Many facts require a change of climate, but those drawn from shells not a sudden one.— It has not yet been proved that the animal in the ice of Siberia & these bones belong to the very same epoch.— with the above supposition they could not.— for are one of animated dying, when he it lived, might easily be washed into the sea. but his its rem flesh would necessarily directly decay. from the warmer climates

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(a) I only try attempt to show. that some of those materials which would be called Diluvium are regular marine depositions.—

(b) I do not overlook that on coast of Patagonia new facts make me believe there has in that case been no great change of climate.—

؟ Would the Carcase of animal dried up as Horses & Mules are seen in the dry plains of S. American float or sink?—

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For the animals in ice I must return to the not very satisfactory explanations which have ^often been offered.— viz a very continental climate.— migratory habits.— the chance that the animals did not require quite the temperature of the torrid zone. (mem: a before Tigers. of India; Puma; and even Jaguar of S. America) the possibility of rapid river in the winter season floating the carcass till it was enveloped in ice & so carried into an Arctic ocean deposited an a plain which subsequently has risen onto dry land.— &c &c

I may notice that this class of cliffs in T. del Fuego has most frequently its form wet with trickling water

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