90 BUREAU OF AMERICAN ETHNOLOGY [Bti.i..33 



(b) Observing the condition of the bones, it is noted th'at the color, 

 surface markings, consistency, discolorations, and other character!- 

 tics are much the same at all levels; the differences are no greater 

 than those observed in the different parts of a single skull -or in 

 specimens in immediate proximity to one another. Such could 

 hardly be the case if some of the bones were thousands of years more 

 ancient than others. The chemical action of the soil, coupled with 

 that of organic elements within it, on human bones in some instances 

 may be very slight, yet it is incredible that no marked differences 

 should be perceptible in the effects of these agencies on bones of the 

 Glacial or the immediately post-Glacial period and those of recent 

 centuries. 



This brings us directly to the very important concurrent fact of 

 the total absence from any of the bones of perceptible fossilization. 

 Such a condition would be hard to explain in bones dating from the 

 period of the original loess deposit and under the circumstances in 

 which the specimens in question were found. It is true that minor 

 grades of mineralization, which ma}^ be difficult of detection, occur in 

 rare instances in certain pleistocene sands or in perpetually dry cave 

 deposits, but the fine Nebraska loess presents different conditions. 

 The fire-hardening at one of the higher levels in the mound was not 

 sufficient to keep out moisture and air, whose presence facilitates 

 physical and chemical changes in inclosed bones. At the time of our 

 visit to the locality in January the earth was found to be frozen at a 

 level lower than the baked layer. To overcome this difficulty of 

 absence of perceptible mineral replacement, and even of infiltration 

 of the specimens, those who would prove that the deeper-lying bones 

 from the Gilder mound are geologically ancient should produce satis- 

 factory specimens of bones, unquestionably ancient yet non fossilized, 

 from deposits of the same nature and existing under the same con- 

 ditions. 



Only one piece, the fragment of a lower jaw, shows changes such 

 as cuiild have been produced by exposure to the elements, even for 

 a moderate length of time. On none of the other bones do we find 

 the easily recognizable results of bleaching or cracking caused by 

 exposure to the sun, or of superficial abrasion that could be attrib- 

 uted to water action. The etching or pitting of the surface observed 

 in some of the bones is due to the action of minute roots or to corro- 

 sion by chemical agencies in the soil or in percolating water-. 

 These features are common to bones embedded for even short periods 

 in various soils. 



(c) Numerous bones from the different levels show marks due to 

 the gnawing of rodents and also cuts made by some sharp implement 

 wielded by human hands. The tooth marks indicate that at some 



