and buried elsewhere.

After the offerings had been flung into the fire, while it was yet
glowing on the altar, earth or sand was heaped over them for a few
inches, then successive layers of earth and sand, or ashes, clay, or
gravel. Sometimes the altars were used several different times, in which
case a layer of clay several inches thick was laid over the old altar.
In one case three layers had been burned in before the final addition of
earth and sand were heaped over it. These strange monuments of a by-gone
people hint to us of mysterious rites. We wish we had more positive
knowledge of the ceremonies they commemorated; but at present we must
rest satisfied with conjecture.

The next class of mounds are known as burial mounds, some of which are
stratified, and resemble the so-called altar mounds. A mound explored
in Butler County, Ohio, had in the center a layer of clay an inch thick,
which had been burned until it was red. Underneath this was another
layer of clay, beneath which was found charcoal, burnt cloth, and
charred bones. Mr. Foster thinks that in this mound the body was placed
on a rude altar, fires were lit, and that while yet burning, clay was
thrown over it all, and that then fires were built all over the mound,
sufficient to burn the clay for an inch in thickness.<21> We have also a
description of a group of mounds explored near the Mississippi River, in
which there were evident signs of cremation. At least in several mounds
fires had been built close above the bodies. But in cremation other
victims may have been burned to accompany the departed chiefs or
warriors. In one mound evidence of such a custom was observed.

In another mound the center was found to be a mass of burned clay
interspersed with calcined human bones. No less than ten or fifteen
bodies had been burned here. "They must have worshiped some fierce ideal
deity, and the ceremony must have been considered of great importance
to have required so many victims." This may have been, however, nothing
more than simple cremation.<22>

Pidgeon has described mounds in Minnesota, in many respects like the
altar mounds. In one case he mentions there was an altar or pavement of
stone on the original surface of the ground, a few feet above which was
a layer of clay, showing the action of fierce and long-continued fires.
We furthermore are told that cremation, especially of chiefs, was more
or less common among the Village Indians of North America,