Stone, metal, and shell artifacts recovered at Menoken show that its people participated in trade systems that spanned the continent, probably through down-the-line exchange rather than by traveling to distant sources themselves. Items valued by many social groups moved across great distances through the hands of owners speaking many languages. Tiny obsidian pieces found in excavations most likely came from near present-day Yellowstone National Park, about 520 miles away. The most surprising metal discovery was six very small artifacts of native raw copper dating to AD 1200, whose nearest source is in extreme eastern Minnesota. Marine shell ornaments may have come from the Gulf of Mexico, the Atlantic Ocean, or the Caribbean Sea, while other shells from a nearby creek or the Missouri River could have served as gaming pieces, paint dishes, or decorative ornaments. Excavations also uncovered fossil shells, including two species of fossil freshwater snails from a 60-million-year-old geologic formation along the Missouri River and a fragment of a marine cephalopod or ammonite.