Expansion of a medical center in Mississippi has been halted after about 2,000 unmarked graves were found in the location.

The University of Mississippi Medical Center in Jackson was clearing the area last month when the neatly lined up graves were found just below the surface, reports CNN.

It is believed that the graves are from the Mississippi State Lunatic Asylum, which was opened in 1855 and was a home for 150 patients. The medical center must now determine what to do with the apparent ancient graveyard. For the time being, the campus will hold off on its expansion of the medical center.

According to USA Today, officials had planned on building another parking structure.

The school has determined that they can’t afford to have the graves moved, as it would cost about $3 million to move all the burials.

“We can’t afford that,” Dr. James Keeton, dean of the medical school, said.

The graves have not been opened at this time, but officials assumed that there aren’t much in the way of personal remains left in the graves.