Archaeologists aren't sure why Mississippian Indians engraved small sandstone tablets with birdman images and crosshatching 1,000 years ago.
Maybe the tablets were used as visual aids for spiritual storytelling. Maybe they were dipped in dye and stamped on deerskin to create patterns.
"Maybe (a tablet) was displayed when you were traveling from one place to another," said Bill Iseminger, assistant site manager at Cahokia Mounds State Historic Site in Collinsville. "It was a passport to show your rank or status or authority."
Whatever their purpose, the tablets are considered archaeologically significant because they provide rare pictures from an ancient culture.
Cahokia Mounds has a newly discovered Mississippian tablet, thanks to Elizabeth Kassly, 50, of Swansea, who donated it to the historic site. It's now on display in the interpretive-center lobby.
"I think it was just meant to be at Cahokia Mounds," said Kassly, a contract archaeologist with Powell Archaeological Research Center in Fairmont City. "Because of its potential, because of the stories it can tell."
The tablet actually is half a tablet because one side is broken off. It's about the size of a playing card, only thicker. It's estimated at 800 years old.
Kassly found the tablet in 2000 while surface collecting on a farm near Valmeyer in her free time. It's known as the Kassly-Schaefer Birdman Tablet because Vernon Schaefer owns the farm.
The front shows a birdman's dotted torso, fringed kilt-like garment and outstretched right wing, and a rattlesnake-like image across the top. Crosshatching covers the back.
"Birdman symbolism of similar hawk or falcon dancers is common in Mississippian iconography," according to interpretive materials. "... The meaning here is not clear with part of the left side and the head missing and the snake element in place of it, but raptorial birds are known to represent the 'upperworld' (spiritual world), humans 'this world' and snakes the 'underworld.'"
Cahokia Mounds is the former location of an American Indian city that flourished from about 950 to 1350 with a peak population of 15,000 to 20,000 residents known as Mississippians.
The historic site has portions of several sandstone tablets, but only one that's whole. It was found during a 1971 archaeological dig near Monks Mound.
That tablet is engraved with a different birdman image. It serves as the historic site's logo and appears on area highway bridges.
Officials believe the Kassly-Schaefer Birdman Tablet may have been engraved in the Cahokia Mounds area. The Mississippian artist probably used a flint tool.
"The thought is, maybe (tablets) were made here and distributed or carried to other places as Cahokia's influence spread," Iseminger said. "It could have even been like missionaries spreading the word about their beliefs."
(Original headline: Swansea woman donates birdman tablet to Mounds )
