WILMINGTON, Ill. (AP) — A group conducting an archaeological dig in northern Illinois has found pieces of broken pottery, projectile points and other artifacts dating to the 1600s.

Two University of Notre Dame professors have been leading summer volunteers on an exploration at the Midewin National Tallgrass Prairie. The project at the Middle Grant Creek Site is revealing how people of the Oneota culture lived in the area four centuries ago.

Earlier this month volunteers digging in a 6-foot-deep pit found projectile points made of rock that would have been used for hunting. They’ve also found painted pottery and needles made from bones, which were likely used to weave mats from tallgrass.

The group is gathering evidence to reconstruct the environment and ecology of the last prehistoric culture of the upper Midwest.