Archaeologists in Delaware have discovered the gravestone of a Civil War soldier that may provide a vital clue in uncovering a long-lost African-American cemetery.

Experts working at a property near Frankford, Sussex County, found the headstone bearing the name “C.S. Hall” and the details “Co. K, 32nd U.S.C.T.” This refers to Company K of the 32nd U.S. Colored Troops, which was a designation for African-American soldiers, according to Delaware’s Division of Historical and Cultural Affairs.

Working under the guidance of the Delaware State Historic Preservation Office, archaeologists hired by the private landowner uncovered at least other nine graves at the site, which is known as the Orr Property, or Hall Plantation.

Experts have not yet matched the headstone to a specific grave, and no information is known about the people buried at the site. However, the site is known to the local community as containing the remains of African-Americans that lived in the area, officials say.