CHESTER, Ill. (AP) — Anthropology students at Southern Illinois University at Carbondale have discovered remnants of an army fort near the community of Chester that was once visited by the Lewis and Clark expedition.

In a news release, SIU Carbondale says the students were searching the area after concluding that Fort Kaskaskia, occupied by the U.S. Army in 1803, didn’t stand atop the site of a fort the French occupied a half century earlier as was long believed. The discovery of an American uniform army button, early 1800s chimney brick and other objects led them to conclude that the fort stood about 300 meters away.

Mark Wagner from the Center for Archaeological Investigations says that since last year’s discovery, the students have returned to the site to learn more about the fort.