DISCOVERIES ATTRIBUTED TO EARLY MAN 15 
Professor Gregory s report (p. 29) throws an entirely new light 
on the geological conditions in the Ayahuaycco gulch. He con 
cludes : 
It is unprofitable, from a geological standpoint, to work out the details of 
erosional history in and about Cuzco, because of the extensive modification of 
slopes and terraces resulting from cultivation and flood-water irrigation. How 
ever, the evidence indicating periodic destruction and building of terraces, 
even within the past 100 years, removes the necessity of ascribing great an 
tiquity to animal bones, parts of human skeletons, and fragments of pottery 
found along stream banks and which may have been deposited on terraces or 
on banks, or in the numerous small cave-like openings in the gravels, to be 
transported, buried, or reexposed during alternating processes of deposition 
and degradation. It is interesting to note that in the canyoned tributaries of 
the Sappi and of streams leading from the limestone plateau and from the 
sandstone highlands bordering the Cuzco Basin on the south valleys from 
which terraces and slides have been removed and whose banks offered no 
temptation io occupation, valleys whose present precipitous gravel walls are 
clearly of glacial age no traces of human occupation were revealed by careful 
search. From these same gravels, however, mastodon bones have been col 
lected, on the Huancaro and in the lower Cuzco Valley. The fact that these 
bones from the Ayahuaycco gravels are of modern types . . . obviously cor 
roborates this view of depositional history, and also indicates important climatic 
changes since the Spanish conquest. 
It will be noted that the explanations given in this paper are chiefly of 
negative value so far as archaeological research is concerned. That man 
existed in South America in glacial or preglacial times, arid that the human 
bones discovered in the Ayahuaycco Quebrada &quot; appear to be from 20,000 to 
40,000 years old &quot; as tentatively held by Bowman, is not definitely disproven by 
the field studies of the present writer. On the other hand, the geologic data 
do not require more than a few hundreds of years as the age of the human re 
mains found in the Cuzco gravels. 
Dr. Eaton, in a further study of the animal bones found with the 
remains of the &quot; Cuzco man.&quot; succeeded, in the first place, in a definite 
identification of the first rib, which looked like that of a bison, as that 
of a cow of the kind raised on the elevated pastures about Cuzco, 
while the canine bones may be referred to a dog. 
The site of the discovery of the bones of the &quot; Cuzco man &quot; was 
carefully examined, and Dr. Eaton states : 
After studying the form and composition of the walls of the quebrada and 
examining other deposits of bones both here and elsewhere in the Province of 
Cuzco, I am led to the opinion that the bones excavated in 1911 were not origi 
nally embedded in the basal gravel of the spur at the time when that gravel 
was itself in process of deposition, but were, in all probability, interred there 
at a much later time when the northeast wall of the quebrada had assumed 
more nearly its present contours. [P. 5.] 
In regard to the bones of lower animals accompanying these human remains 
it seems to have been an ancient and common practice in this part of Peru to 
place in the human grave pieces of the flesh of llamas and occasionally, if the 
mute testimony of the bones can be relied on, a dog s entire carcass. There is 
no reason to suppose that this ancestral custom \vould have been discontinued 
