A group of tourists mistakenly stumbled upon what is likely the site of a centuries-old burial ground as they explored an island off the coast of South Carolina, officials said.

The startling discovery was made on Jeremy Cay, a beachfront part of Edisto Island, a site once home to the 19th-century settlement of Edingsville Beach, according to the Colleton County Sheriff’s Office. The group initially believed that they had uncovered fossils, only to realize that what they actually found were skeletal remains.

“Early indications suggest the remains may originate from a long forgotten burial site,” the sheriff’s office said.

Authorities responded to the beach, located some 50 miles from Charleston, and secured the area. The remains — which included a skull and a scattering of separated bones — were collected from the beach destination and are slated to undergo forensic analysis to determine their origin and age, Newsweek reported.

During the 19th century, Edingsville Beach was a settlement made up of about 60 homes, according to the Edisto Island website. It was also a popular vacation destination for wealthy Southern families, with residences overlooking the sea and a nearby marsh.