[mikeus_maximus]

They employed exotic materials such as shell from the Gulf of Mexico, copper from present-day Michigan, mica from what is now North Carolina, and obsidian from the land that became Wyoming.

The Mississippian Culture had a fascinating trade network. I've been to the museums at the Etowah mounds near Rome, Georgia, and at mounds near Spiro, Oklahoma- what, 1000 miles away? They show the extensive interchange of goods and materials between these peoples, east, west, north and south.

What I don't understand is how an article like this can neglect the most famous Mississippian mound complex of all: the Serpent Mound in southern Ohio.

[Betis70]

The Serpent mound is earlier and part of the Adena/Hopewell complex. Slightly different mound construction, not quite as organized and earlier than the Mississippians.

Cahokia is probably the biggest Mississippian city, along with Etowah and Moundville in Alabama.