Buenos Ayres and the Provinces of the Rio de La Plata / Their Present State, Trade, and Debt

by Sir Woodbine Parish

Such, I conceive, may have been the origin of the far spread formation of the present pampas or plains, throughout which are to be found the fossil remains of gigantic animals of long lost species, such as the megatherium and mastodon, and other monsters yet unnamed, which in former ages may have grazed upon the abundant pastures produced in the rich loamy lands saved from the waters; whilst beneath, in strata of marine shells, are no less incontestable evidences of the ancient bed of the ocean.

It cannot be expected that, in a country so uniformly level as the pampas, sections of sufficient depth will frequently occur to exhibit the underlying strata. They must be looked for at the outlying extremities of the formation, where the upper bed thins out,—to use a geological term. Now there is nothing that I know of to interrupt the uniformity of the stratum between the southern shore of the Plata on the one side, and the eastern base of the Andes on the other, and at both these extremes marine remains are strikingly exhibited.

General Cruz, in his journey from Antuco to Buenos Ayres (noticed in chapter viii.), in passing through the valleys in the lower ranges of the Cordillera, immediately before reaching the pampas, was exceedingly struck with the abundance of marine remains thereabouts. He says, in his diary, "In all the hills and valleys under the Cordillera, as far as the river Chadileubu, a great quantity of marine remains are met with, some of them constituting a sort of limestone. Not only may these remains be observed upon the surface, but also at great depths below it, in the sections formed by the torrents as they descend from the mountains: there can, therefore, be no doubt that the waters of the sea once occupied the place of the land in those parts."

Proceeding eastward, by the base of the mountain ranges of San Luis and Cordova, which bound the pampas to the north, we have the testimony of water-worn rocks and beds of shells in that direction, from Schmitmeyer, Helms, and other travellers, at Portezuela and on the banks of the Tercero; and beyond the Sierra de Cordova, on the great river Paranã, near Santa Fé, Mr. Darwin found in the cliff which skirts the river a stratum of marine shells distinctly exposed a little above the level of the water, and with the alluvial bed over it, forty or fifty feet thick, containing bones of extinct mammalia.

Here, then, I think, we may trace, all but continuously, the northern and western shores of a gulf, which must have been nearly as large as that of Mexico, and not very unlike it, perhaps, in general outline. Travelling south from Santa Fé, along the shores of the Plata, which bounds these pampas on the east, we find, at distances varying from one to six leagues inland from the river, and from fifty to one hundred and fifty miles from the sea, large beds of marine shells, which the people of those parts quarry for lime. From these deposits I have myself specimens of Voluta Colocynthis, Voluta Angulata, Buccinum Globulosum, Buccinum Nov. Spe., Oliva Patula; Cytheræa Flexuosa? Mactra? Venus Flexuosa, Ostrea, &c. In some places these shells are so compact as to form a sort of limestone, easily worked when first dug out, and hardening afterwards on exposure to the air. The church of Magdalena upon the coast is built of this material. They are generally in good preservation, and some of the species appear almost identical with those found upon the coasts of Brazil; others, on the contrary, found with them are not known. There is one, found generally by itself, unmixed with others, which is particularly interesting on this question, as strikingly proving the gradual growth of the pampas; it is the small mya, named potamo-mya by Sowerby, usually found in estuaries at the junction of the fresh and salt water, and the existing type of which is now to be met with at the mouth of the Plata; but the bed from which my fossil specimens were taken is at the Calera de Arriola, to the north of Buenos Ayres, nearly 150 miles from its present habitat; and there (I think manifestly proved by these little shells) must have been once the mouth of the mighty estuary, which is now more than 150 miles below it.

I must not omit to state that all these marine deposits are found in situations more or less above the present level of the ocean; this, in the neighbourhood of the Cordillera, which is so continually liable to volcanic disturbances, may be accounted for; but it leads to other speculations in the flat alluvial plains towards the Plata, where the phenomenon of an earthquake is utterly unknown, and where the apparently perfect horizontality of the strata would seem to negative the idea of any violent action by which it might have been upheaved.

Mr. Bland, one of the North American Commissioners sent to Buenos Ayres in 1818, reasoning upon the quantity of saline matter found in the pampas, hazards, as he says, the conjecture that the pampa formation "may have been gently lifted just above the level of the ocean, and left with a surface so unbroken and flat as not yet to have been sufficiently purified of its salt and acrid matter, either by filtration or washing:" and undoubtedly such saline matter does exist very extensively over this formation. Many of the running waters, as their names denote, are rendered brackish by it; and lakes which have no outlet become saturated with it, and deposit it in regular beds, where in the dry season it may be collected in any quantity. But it does not necessarily follow that it has been left there by the ocean: we know that salt abounds in the Andes, and that extensive beds of it occur, particularly in those parts of them from which we may conjecture that the greater part of the waters of the pampas are derived; and if for a moment we can suppose the pampas themselves to have originated in sedimentary deposits from those mountain chains, we must I think equally admit that the alluvial soil washed down can hardly fail to be impregnated with so soluble a substance as the salt which abounds in them. In a country of more varied surface we might expect the briny particles to be carried off by the streams and lost in the sea; but in the dead levels of the pampas the greater part of the streams themselves are lost long ere they reach the ocean. The waters deposit their sediment over the surface, and the salt is left to amalgamate with the mire of the marshes, until perhaps again the rains collect it, and either partially carry it off in brackish streams, or deposit it in the basins of the inland lakes, in which it is so abundantly found. That it is a superficial deposit I think is proved by the fact that (as elsewhere noticed) in the immediate vicinity of some of the saline lakes and rivers in the pampas, and where the surface of all the surrounding country appears to be incrusted with salt, the people dig wells, and find perfectly fresh and potable water, as I understand, at a depth of from twenty to fifty feet. The same may be said to occur throughout the city of Buenos Ayres, where all the wells which do not penetrate the tosca produce water more or less brackish, whilst those which go below it are sweet. Some of the best water I ever tasted was from a well sunk in the sandy stratum below the clay at Mr. Brittain's quinta outside the city. Further, I imagine that the discovery of the remains of land animals so generally throughout this formation is in itself conclusive of its deposition subsequently to the existence of the ocean in those parts, the ancient bed of which it must very considerably overlie.

To speak of the megatherium alone, its remains have been found in all parts of the pampas, from the river Carcaraña, in the province of Santa Fé, to the south of the Salado, a distance of nearly 300 miles in a direct line, and in all the intermediate country. Such remains are much more common than is supposed, and I am satisfied might frequently be met with if searched for during the dry season, or after long droughts, either in the banks of the rivers, or in the beds of some of the numerous lakes which are then dried up. All the remains I sent home were so discovered, and so were those sent to Madrid by the Marquis of Loreto, which were found in the bed of the river Luxan, a short distance to the north of the city of Buenos Ayres. The great skeleton I obtained was discovered in the river Salado, to the south of Buenos Ayres, after a drought of unusually long continuance, by a peon in the service of the Sosa family, who, attempting to cross the river at an unfrequented spot, was struck by the appearance of a large mass of something standing above the surface of the water, and which, supposing at first to be some part of the trunk of a tree, he determined to get out if possible: in this he was assisted by some of his brother peons, who, throwing their lassoes over it, succeeded in dragging it out, fortunately without injury, for it proved to be nearly the entire pelvis of the megatherium: with it were also brought up several of the other bones, and amongst them some of the vertebræ. To the peons the pelvis luckily appeared to be useless: turn it which way they would, they all agreed that it did not make half so comfortable a seat as either a bullock's or a horse's head; but the vertebræ did not so easily escape, and in a place where not a stone is to be seen, were eagerly seized upon as excellent substitutes to boil their camp-kettles upon. The smaller ones being best suited to the purpose were the first to disappear, which may account for the deficiency of all the cervical vertebræ as well as of many of the smaller bones of the feet and other parts. After a time it was suggested that the pelvis and some of the largest bones should be sent as curiosities to the owner of the estancia on which they were found, Don Hilario Sosa, at whose house in Buenos Ayres I first saw them. He was good enough, seeing my great anxiety to obtain possession of them, after exhibiting them to his friends, to place them at my disposal, and to allow me to send people to his estancia to search for the remainder of the skeleton: by their exertions many other portions of it were saved; and but for the destruction of some by the country-people, as described, and of others which, having been taken out in the first instance, had remained exposed for some months to the sun, and had become so brittle in consequence as not to bear removal, the skeleton would have been tolerably perfect. As it is, it was very fortunate that amongst the parts preserved were some of those which are wanting in the skeleton at Madrid, especially the bones of the tail, which singularly corroborate the anticipations of Cuvier, whose description of this remarkable monster was drawn from a representation of that specimen, the only one known to exist till mine reached Europe.

M. Cuvier was not I believe aware of the grounds which now exist for supposing that the animal was covered with a coat of mail, like the armadillo, which has led other comparative anatomists to ally it to that family. There were no remains of such a shell appertaining to the specimen at Madrid, neither were any found with the bones which I have spoken of as discovered in the Salado. Portions, however, of a shelly covering in a fossil state, which must have belonged to some gigantic animal, had been at various times dug up in the pampas, which had excited the attention and speculations of the curious. Even father Falkner in his account of the country speaks of them:—he says, that he himself found the shell of an animal composed of little hexagonal bones, each bone an inch in diameter at least, and the whole shell nearly three yards over: it seemed to him to be in all respects, except its size, the upper part of the shell of an armadillo.

The researches I set on foot after finding the skeleton in the Salado led to fresh discoveries, which, if they do not identify these shells with the megatherium, must lead us to conclude that these regions were once inhabited by other gigantic animals no less extraordinary. When the country-people saw the eagerness with which the big bones from the Salado were sought for, they were not backward in speaking of other places where similar remains had been met with, and were still, as they believed, to be found. Upon this information I once more despatched my agent to the south of the Salado, and the governor, Don Manuel Rosas, taking an interest in the matter, was good enough to furnish him with a letter of recommendation to the local authorities, desiring them to give him not only protection, but every assistance he might need to ensure his success. In little less than three weeks we were repaid by the discovery of two more enormous skeletons on the estancias of the governor himself, called Villanueva and Las Averias, and in both instances with the novelty of their being encased in a thick coating or shell resembling that of the armadillo. The first, found at Villanueva, though still of gigantic proportions, appears to have been very much smaller than that which had been taken out of the Salado: it was discovered in the bed of a small rivulet, and upon exposure to the air nearly all crumbled to dust. The only portions it was possible to preserve being part of a scapula, a small portion of the jaw with one small but perfect tooth remaining in it, and a fragment of a hind leg, with some of the feet bones. The shell lay, as Mr. Oakley, my agent, described it, a little below the principal mass of the bones, looking like the section of a huge cask; the form of it when first discovered appeared natural and perfect, but it would not bear to be lifted out of its bed, and broke into small pieces and crumbled away immediately.