CLEMSON, SC (NewsNation/WSPA) — Clemson University officials said Monday that ground-penetrating radar revealed the possible locations of more than 215 unmarked graves believed to be those of Black slaves from the 1800s.

The possible location of the graves is in the Woodland Cemetery on Clemon’s main campus, the university said in a news release.

Clemson officials said the graves are believed to be Black slaves who worked from 1830 to 1865 on John C. Calhoun’s Fort Hill Plantation. Some of the graves could also be from sharecroppers and Black laborers who were involved in the construction of Clemson College from 1890 to 1915, officials said.

Tests showed disturbed soil about five feet below the ground, which indicates a possible grave. The potential graves are west of the Calhoun family plots.

Officials said the university has reached out to leaders in the Black community, and that Dr. Rhondda Thomas, the Calhoun Lemon Professor of Literature at Clemson, plans to talk with families to figure out who could be buried in the cemetery and how to honor them.

“We are committed to taking all the critically important actions to enhance these grounds, preserve these grave sites and to ensure the people buried there are properly honored and respected,” said Smyth McKissick, chairman of the Board of Trustees. “Clemson is dedicated to developing and sharing a full and accurate history of this area and to develop a preservation plan to protect it and those who rest here.”

Th university also hired a historian to assist Dr. Paul Anderson, Clemson’s historian who is leading the research, and all of the work will be published on a website Clemson has started to help document the school’s role in Woodland Cemetery.

The university said historic markers were placed at Woodland Cemetery in 2016, designating the area as the site of the Fort Hill Slave and Convict Cemetery.

NewsNation affiliate WSPA contributed to this report.