1250 A.D. by ancestors of the Natchez Indians.
In Iowa and Louisiana.
The Mound Builders who were Adena and Hopewell and Mississippian.
mound builders
building mounds such as the serpent mound
mound indians ate corn , rice , wheat , bison , corn mammoth , deer , mastadons
indians
You can't. Softball doesn't have a raised mound.
early American Indians
wood
the ohio river
They are earthen mounds.
They build enormous structures