182 BUREAU OF AMERICAN ETHNOLOGY [bull. 52 



any in the cave. Thus the changes in the bones of animals of still- 

 existing species were evidently similar in general to those in the 

 human bones, and there is equal justification in both cases for con- 

 sidering the remains contemporary with the extinct species. 



In view of these considerations, petrifaction as an index of age in 

 this particular cave must necessarily be regarded as of little value. 

 The potency of mineral substances of the soil in altering bones is 

 very pronounced, and this potency is materially increased by the 

 presence of water, especially when the latter carries in solution, 

 as it often does, the organic and inorganic constituents favoring 

 f ossilization. Such agencies are sufficient to account for the changes, 

 within a few centuries, observed in the human and recent animal 

 bones found in the Sumidouro cave. On the western coast of Florida, 

 as reported by Vaughan and the writer on another occasion,^ similar 

 agencies are causing the rapid petrification of human bones and 

 other objects subject to their influence, and these have produced 

 also in relatively recent times in other parts of America changes 

 in bones very much like those observed in the Sumidouro cave. 

 One such instance is the cranium reported from the mouth of the 

 Amazon by Lacerda (see p. 171), and many striking examples are 

 seen among the brown and blackish-brown mineralized human 

 remains collected by Moreno and also by the writer from the super- 

 ficial and relatively recent alluvial deposits in certain parts of the 

 valley of the Rio Negro. ^ 



That the fossil animal bones from the cave under consideration 

 presented the same degree of petrifaction as the associated human 

 bones, rests only on statements and superficial evidence, but it is 

 quite obvious, as already mentioned (see p. 7), that petrifaction 

 under given conditions may proceed only to a certain stage, where it 

 necessarily stops or becomes exceedingly slow. Hence two bones of 

 widely different ages could well present the same aspect of petrifac- 

 tion, a condition wliich in all probability exists in the Sumidouro 

 cave. 



There remain to be reviewed the anthropologic characteristics 

 of the bones, and the first query that presents itself in this connec- 

 tion is. What has become of the low sloping foreheads which Lund 

 so accentuated in liis letters ? It is certain that none of the examples 

 described present any such feature. (Pis. 16, 17.) It may also 

 be asked, Where are the human bones from the five or six other 

 caves mentioned as having contained such remains? Also, trace 

 seems to be lost of the skulls from the Sumidouro cave (excepting 

 the specimen in Rio de Janeiro) bearing the characteristic wounds 

 which Lund mentioned. However, this last point is quite immaterial. 



1 See Bulletin 33 of the Bureau of American Ethnology. 



2 See chapter on The Ancient Patagonians and that or fiie Homo pampxus. 



