slabs; some round, others polygonal; some dome-shaped, others
square, and others box shaped, or parallelograms. Reference is
made at present only to the last mentioned--the box shaped type,
made of stone slabs. If the evidence shows that this variety is
found only in certain districts, pertains to a certain class of
works, and is usually accompanied by certain types of art, we are
warranted in using it as an ethnic characteristic, or as
indicating the presence of particular tribes. If it can be shown
that graves of this form are found in mounds attributed to the so-
called mound-builders, and that certain tribes of Indians of
historic times were also accustomed to bury in them, we are
warranted in assuming that there was a continuity of custom from
the mound-building age to historic times, or that graves found in
the mounds are probably attributable to the same people (or allied
tribes) found using them at a later date. This conclusion will be
strengthened by finding that certain peculiar types of art are
limited to the regions where these graves exist, and are found
almost exclusively in connection with them.

These graves, as is well known, are formed of rough and unhewn
slabs or flat pieces of stone, thus: First, in a pit some 2 or 3
feet deep and of the desired dimensions, dug for the purpose, a
layer of stone is placed to form the floor; next, similar pieces
are set on edge to form the sides and ends, over which other slabs
are laid flat, forming the covering, the whole when finished
making a rude, box-shaped coffin or sepulcher. Sometimes one or
more of the six faces are wanting; occasionally the bottom
consists of a layer of water-worn bowlders; sometimes the top is
not a single layer of slabs, but other pieces are laid over the
joints, and sometimes they are placed shingle-fashion. These