XL ANNUAL REPORT OF THE DIRECTOR 
burial and of burial mounds, the gradation from one to the 
other is so complete as to leave no marked line of distinction. 
The stratified mounds in which the hard clay or mortar cover- 
ing over the remains is found may be the work of tribes dif- 
ferent from those which constructed the small unstratified tu- 
muli, but the distinctions between the two classes are not such 
as to justify the belief that they are to be attributed to a dif- 
ferent race or to a people occupying a higher or widely dif- 
ferent culture status. 
Having reached this conclusion, it is necessary to take one 
step further in the same direction and ascribe the singular 
structure known as “effigy mounds” to the same people. The 
two classes of work are too intimately connected to admit of 
the supposition that the effigy mounds were built by one race 
or people and the conical tumuli by another. 
The works of different tribes may frequently be found in- 
termingled on areas over which successive waves of popula- 
tion have passed, but that one part of what is clearly a system 
is to be attributed to one people and the other part to another 
people is an hypothesis unworthy of serious consideration. 
The only possible explanations of the origin, object, or mean- 
ing of these singular structures are based, whether avowedly 
so or not, on the theory that they are of Indian origin. 
The facts that the effigy mounds were not used as places of 
sepulture and that no cemeteries save the burial mounds are 
found in connection with them afford almost conclusive proof 
that the two, as a rule, must be attributed to the same people, 
that they belong to one system. 
The vexed question Who were the mound builders? is prop- 
erly stated as follows: 
Were all the mounds and other pre-Columbian works explored 
in that portion of the United States east of the Rocky Mount- 
ains built by the Indians found in possession of this region at 
the time of its discovery and their ancestors, or are they in 
part to be attributed to other more advanced races or peoples, 
such as the Aztec, Toltec, Pueblo, or some lost race of which no. 
historic mention exists? 
