ANEJO SI G. NORMAS RELACIONADAS CON LA APLICACIÓN DEL DB SI

At Rancho La Brea, once on the western outskirts of Los Angeles, and at present in the immediate neighborhood of the luxurious shopping center of that city, bones of extinct animals and of still living species are found in abundance in asphalt mixed with clay and sand. In 1875 some fossil remains of this bituminous deposit were described for the first time. By then thousands of tons of asphalt had already been removed and shipped to San Francisco for roofing and paving. 1

Beds of petroleum shale (rock of laminated structure formed by the consolidation of clay), ascribed to the Tertiary Age, having in many places a thickness of about two thousand feet, extend from Cape Mendocino in northern California to Los Angeles and beyond, a distance of over four hundred and fifty miles. The asphalt beds of Rancho La Brea are an outcrop of this large bituminous formation.

Since 1906 the University of California has been collecting the fossils of Rancho La Brea, "a most remarkable mass of skeletal material." When found, these fossils were regarded as representing the fauna of the late Tertiary (Pliocene) or early Pleistocene (Ice Age). The Pleistocene strata, fifty to one hundred feet thick, overlie the Tertiary formations in which the main oil-bearing beds are found. The deposit containing the fossils consists of alluvium, clay, coarse sand, gravel, and asphalt.

Most spectacular among the animals found at Rancho La Brea is the saber-toothed tiger (Smilodon), previously unknown elsewhere in the New or Old World, but found since then in other places too. The canine teeth of this animal, over ten inches long, projected from his mouth like two curved knives. With

this weapon the tiger tore the flesh of his prey.

The animal remains are crowded together in the asphalt pit in an unbelievable agglomeration. In the first excavation carried on by the University of California "a bed of bones was encountered in which the number of saber-tooth and wolf skulls together averaged twenty per cubic yard." 2 _{No fewer than}

seven hundred skulls of the saber-toothed tiger have been recovered. 3

Among other animals unearthed in this pit were bison, horses, camels, sloths, mammoths, mastodons, and also birds, including peacocks.

In the time following the discovery of America this region of the coast was rather sparsely populated with animals; early immigrants found only "semi-starved coyotes and rattlesnakes." 4 _{But when Rancho}

La Brea received its skeletons "there lived an amazing assemblage of animals in Western America." 5

To explain the presence of these bones in the asphalt, the theory was offered that the animals became entrapped in the tar, sank in it, and were embedded in asphalt when the tar hardened. However, the large number of animals that filled this asphalt bed to overflowing is baffling. Moreover, the fact that the vast majority of them are carnivorous, whereas in any fauna the majority of animals would be herbivorous - otherwise the carnivores would have no victims for their daily food - requires

explanation. So it was assumed that some animal, caught in the tar, cried out, thus attracting more of its kind, and these were trapped, too, and at their cries carnivorous animals came, followed by more and more.

This explanation might be valid if the state of the bones did not testify that the ensnarement of the animals by the tar happened under violent circumstances. Oil from which the volatile elements have evaporated leaves asphalt, tar, and other bitumens. "As the greater number of the animals in the Rancho La Brea beds have been entrapped in the tar, it is to be presumed that in a large percentage of cases the major portion of the skeleton has been preserved. Contrary to expectations, connected skeletons are not common." 6 _{The bones are "splendidly preserved} 7 _{in the asphalt, but they are "broken, mashed,}

contorted, and mixed in a most heterogeneous mass, such as could never have resulted from the chance trapping and burial of a few stragglers." 8

Were not the herds of frightened animals found at La Brea engulfed in a catastrophe? Could it be that at this particular spot large herds of wild beasts, mostly carnivorous, were overwhelmed by falling gravel, tempests, tides, and raining bitumen? 9 _{Similar finds in asphalt have been unearthed in two other places}

in California, at Carpinteria and McKittrick; the depositions were made under comparable

circumstances. The plants of the Carpinteria tar pits were found, with one exception, to have been "members of the Recent flora," or of the flora now living 200 miles to the north. 10

Separate bones of a human skeleton were also discovered in the asphalt of La Brea. The skull belonged to an Indian of the Ice Age, it is assumed. However, it does not show any deviation from the normal skulls of Indians.

The human bones were found in the asphalt under the bones of a vulture of an extinct species. These finds suggest that the time when the human body was buried preceded the extinction of that species of vulture or at least coincided with it; in a turmoil of elements the vulture met its death, as did possibly the rest of its kind, with the saber-toothed tiger and many other species and genera.

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l Cf. J. C. Merriam: "The Fauna of Rancho La Brea," Memoirs of the University of California, 1, No. 2 (1911). 2 Ibid.

3 R. S. Lull: Fossils (1931), p. 28.

4 George McCready Price: The New Geology (1923) , p. 579. 5 Lull: Fossils, p. 27.

6 Merriam: Memoirs of the University of California, I, No. 2. 7 Lull: Fossils, p. 28.

8 Price: The New Geology, p. 579.

9 C. E. Brasseur: Histoire des nations civilisées du Mexique (1857-59), I, 55; Popul-Vuh, le livre sacre, ed. Brasseur (1861). p. 25.

10 R. W. Chancy and H. L. Mason: "A Pleistocene Flora from the Asphalt Deposits at Carpinteria, California," in Studies of

the Pleistocene Paleobotany of California (Carnegie Institution, 1934).

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