298 BUREAU OF AMERICAN ETHNOLOGY [bull. 52 



which in many places assume the form of whole layers, and also in the 

 effects observed on recent bones of animals as well as of man. 



The writer brought an astragalus of a cow picked up among the 

 refuse in front of an occupied hut on the coast near Mar del Plata, 

 which shows marks of cutting with a sharp knife. This bone 

 undoubtedly came from a limb the flesh of which was eaten some 

 years ago by the family occupying the dwelling, but already it pre- 

 sents a metallic luster and a darkened surface as well as increased 

 weight, bemg plainly on the road toward fossilization. 



From slightly farther south, near the Arroyo Corrientes, the writer 

 brought a large part of the pelvis of a cow which had been partially 

 buried and partially exposed to the air; the part that was buried is 

 of a dark color and has a smooth, hard, shining surface decidedly 

 fossil in appearance, while the rest of the bone is quite wliite. Other 

 bones were picked up from the sands and play as, which had been 

 exposed for a long time to the sun and to the wind blast; these 

 are weathered, some hardened and some crumbling, dry, fossil-like. 

 One and the same bone occasionally presents these different features 

 in different parts, which evidently were subjected to unlike con- 

 ditions. Several specimens of the teeth of the common horse were 

 picked up on the broad, flat beach of the Laguna de los Padres, all 

 belonging to the modern horse, hundreds of living specimens of which 

 are feeding about the lake; these teeth are yellowish-brown in color, 

 with blackish somewhat lustrous discoloration in places, and with a 

 surface resembling that of petrified wood. 



Finally, the writer brought from the valley of the Rio Negro, from 

 the mud-soil of a shallow depression in the alluvial surface of the 

 valley, which is occasionally filled with water, the remains of 10 

 Indian skeletons, including several complete skulls, all parts of which, 

 except those for a time exposed to the air where they lay and in 

 consequence bleached, are brownish-black, old bronze-like, shiny, 

 somewhat heavier than normal, and in every way "fossil" in 

 appearance. The teeth even more than the bones look fossil-like 

 and the changes undergone by them are markedly different in the 

 several specimens. The "fossil" as well as the other Patagonian 

 skulls of Moreno belong to this same category. 



The foregoing does not imply that every bone of man or animal 

 on the coast of Argentina will become fossil-like or mineralized in a 

 short time; but such cases are relatively common, and the mere 

 fossilization of a bone can not be taken by itself in any instance, 

 without decisive proofs of geologic and morphologic nature, as a 

 criterion of the antiquity of the specimen. This applies particularly 

 to cases in which the bone is found covered or incrusted with cal- 

 careous matter or concretions, for lime salts are more easily soluble 

 than many other minerals; they are carried not only by the surface, 

 but especially by the underground waters, the latter often rising 



