Men wearing loincloths and hawk feathers sat around a fire and drank the black drink from whelk shells that were etched with winged snakes and raccoons with antlers. The drink, made from a plant found on the southern Atlantic coast, was used in a purification ritual before warfare or Lacrosse games with other tribes. Whoever drank it, threw up.

Twenty-two of the whelk shells and charcoal rubbings of their engraved designs are on display at the Smithsonian's Museum of Natural History through Sept. 9. The Exhibit, "A Shell Game: Reconstructing Designs on Pre-Columbian Shells from Spiro, Oklahoma," is the result of a 14-year-long project sponsored by Harvard's Peabody Museum.

In the 1930s, commercial relic hunters dug up the shells in eastern Oklahoma from an ancient burial mound dating back to the Spiro Indian culture, which lasted from 700 to 1350 A.D.

"the big shots were honored at death by burial with engraved shell cups," said Dr. Bruce Smith, a Smithsonian archeologist. From the Craig Mound in Spiro, the hunters dug up hundreds of pounds of shells, woven garments, stone effigies, copper pendants and shell beads.

Harvard archeologists collected the shells from all over the country, Phillips of the Peadbody Museum devised a way of putting the designs of paper with charcoal rubbings, much like the rubbings school-children do of tombstones.The archeologists then pieced the rubbings together, like a jigsaw puzzle.

Most of the designs depict combinations of different animals. "the Spiro people seem to have a fasicination with the borderline between different animals that don't fit into their taxonomy of the world," said Smith, pointing to one design. "they were intrigued by spiders that cam skin across the surface of water, snakes that fly, and birds that ruled the skies." CAPTION: Illustrations 1 and 2, no caption