12 BUREAU OF AMERICAN&quot; ETHNOLOGY [BULL. 66 
Professor Bowman s report gives geologic details and contains a 
number of interesting conclusions, which illustrate, in view of knowl 
edge acquired later, how easy it is sometimes even for a specialist 
to be in error. He summarizes the results of his study of the case 
as follows: 
The bones found near Cuzco were contemporaneous with the compact gravels 
in which they were embedded. They were disposed in the form of a lense 
about 10 feet long and 6 inches thick. From (1) their disposition with respect 
to each other, (2) their relations w T ith the bedding planes, and (3) their worn 
condition, it is concluded that they were interstratified with the gravel beds. 
The age of the beds thus becomes the critical factor in the interpretation. 
From a detailed study of the geology of the upper Cuzco basin with special 
reference to glacial forms, it is concluded (1) that the beds belong to a 
glacial series, (2) that the bones were deposited during a period of pronounced 
alluviation, and (3) that since the deposition of the bones from 75 to 150 feet 
of gravel were deposited over them and later partly eroded. The age of the 
vertebrate remains may be provisionally estimated at 20,000 to 40,000 years. 
It is only fair to state that in the following paragraph of his 
report Professor Bowman points to weaknesses of the case that 
there is a lack of sharp distinction between certain of the bones 
found with the human remains and referred to the bison, and the 
bones of modern cattle; that &quot;certain canine bones gathered in con 
nection with the human remains can not be said to be unlike those of 
the modern domesticated dog&quot;; and that there is a fair possibility 
&quot;that the bluff in which the bones were found may be faced by 
younger gravel, and that the bones were found in a gravel veneer 
deposited during later periods of partial valley filling.&quot; 
Farther on in Professor Bowman s report some of the above points 
are accentuated : 
The relation of the bones to the surface of the bluff leads to some important 
considerations. The finding of material on the immediate face of the bluff 
does not merely by virtue of that position indicate with certainty natural burial 
during the upbuilding of the formation and reexposure as a result of present 
erosion. Though the bluff is very steep, a number of plant forms cling to it. 
These catch particles of falling or sliding material and even pieces of pottery. 
In a number of cases it was noted that the vegetation responsible for sucii 
obstruction in time dies, and may be entirely or almost entirely removed. Sur- 
ticial objects are then left attached to the face of the bluff, from which they 
may be easily removed. The steeper the bluff the more difficult the retention 
on a sloping surface becomes. The patchy mantle of foreign material is 
always loo^e, unstratified, fine textured, and in strong contrast to the undis 
turbed material directly beneath it. As contrasted to such surface drift, it 
is noteworthy that .the vertebrate remains were not on the face of the bluff, 
but 8 inches back from the face, measuring to the median line of the deposits ; 
also that they were stratified with the gravels, mixed with material of about 
the same texture and composition, and that they lay in a nearly horizontal 
plane. 
