Prehistoric Man he devotes much space to the consideration of the
matter. His ideas on the subject will be understood from the following
quotation:

By the fidelity of the representations of so great a variety of
subjects copied from animal life, they furnish evidence of a
knowledge in the Mississippi Valley, of the fauna peculiar not only
to southern, but to tropical latitudes, extending beyond the Isthmus
into the southern continent; and suggestive either of arts derived
from a foreign source, and of an intimate intercourse maintained
with the central regions where the civilization of ancient America
attained its highest development: or else indicative of migration,
and an intrusion into the northern continent, of the race of the
ancient graves of Central and Southern America, bringing with them
the arts of the tropics, and models derived from the animals
familiar to their fathers in the parent-land of the race. (Vol. 1,
p. 475.)

The author subsequently shows his preference for the theory of a
migration of the race of the Mound-Builders from southern regions as
being on the whole more probable. Wilson does not, however, content
himself with the evidence afforded by the birds and animals which have
just been discussed, but strengthens his argument by extending the list
of supposed exotic forms known to the Mound-Builders in the following
words (vol. 1, p. 477):

But we must account by other means for the discovery of accurate
miniature representations of it (_i.e._ the Manatee) among the
sculptures of the far-inland mounds of Ohio; and the same remark
equally applies to the jaguar or panther, the cougar, the toucan;