274. W. SJ. McGee—Artiicial Mounds of Northeastern Iowa. 
which they may have been designed partly as fortifications, it 
does not readily appear that they subserved any practical use. 
This has led many archeologists to infer that they were con- 
nected with superstitious observances; but it has occurred to 
the writer—and the weight attaching to the view may be esti- 
mated from a comparison of the dimensions given below—that 
their purpose was to record the discovery of a linear unit, and, 
in the absence of a written language, to perpetuate a system of 
measurement. 
ee 
_ The animal mounds are quite similar to those of other local- 
ities, and are almost always associated with the last two classes 
of mounds. In the accompanying figure, three animal mounds 
of a ravine as to admit of the idea that they may have beet 
ward, at the termination of the same ridge, are two embank- 
ments, each forty yards in length. 
