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IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
It is these “Indian Mounds’ 7 in the proposed park area of 
12,000 acres and on the bluff tops of the adjacent neighborhood 
that are to receive our attention in this brief paper. 
To begin with there are four types of earthworks, the work of 
the aborigines, found in Iowa. 
The most common type is the conical (so called) burial mound 
much like half an orange laid with the flat side down. They 
have an average diameter, measured at the base along the original 
surface of the ground, of twenty-five feet, and an average height 
of three to four feet. Some are found with a diameter of over 
sixty feet and a height of eight to ten feet. Others are not over 
fifteen feet in diameter with a height of about a foot. 
For the most part all are built up on the same plan. First an 
inner mound of hard dry clay, over that flat rocks laid irregu- 
larly, then another foot of earth closely resembling the upper 
foot of the surrounding natural surface. 
On the high islands or bordering terraces in the river valley, 
which are usually beds of pure sand with a foot or two of sandy 
soil on top, the mounds appear to be built of the surface soil. 
The material seems to have been gathered from a considerable 
area as no pits from which it might have been taken are ever 
found. 
All conical or round mounds are supposed to be burial mounds. 
But few of the Iowa, mounds in or near the proposed park area 
contain any skeleton remains or artifacts of any kind, so far as 
the writer has had opportunity to excavate them or has been able 
to get information from those who have. 
Personal experience leads the writer to believe that the ac- 
counts of the remarkable finds in these ancient earthworks, so 
far as they exist in northeastern Iowa, or southwestern Wiscon- 
sin, should be heard with a grave suspicion that they were very 
highly colored. In perhaps twenty-five mounds more or less 
thoroughly excavated by the writer there has been found but 
one arrow head and a small crude earthen vessel three inches 
high by two inches in diameter — nothing else. 
Prehistoric pottery, and artifacts of flint and other material 
of which arrow points, knives, and other implements were made, 
and of diorite, granite and copper are very common. But this 
material is found scattered about the fields in greater or less 
abundance according to locality, or is found in the ordinary 
