FALMOUTH, Maine — A large hole in the ground is often nothing more than a nuisance that needs to be filled or covered.

But in the case of one such hole off Hardy Road, it’s a portal to the past.

What is known as the Nathaniel Leighton crypt is believed to have been a burial vault for members of the Leighton family, according to the town’s open space ombudsman, Robert Shafto.

Shafto said the crypt was rediscovered late last winter as part of a housing development being constructed on Hardy Road.

The crypt is noted on a map of the town dating back to 1857, so Shafto said it is at least that old. He said the family that built it – presumably the Leightons – were likely well off.

“This took time and money,” Shafto said, who verified his findings with an archaeologist.

The crypt is about six feet wide, eight feet long, and at least six feet deep. It is the only known crypt of its kind in Falmouth, Shafto said.

Shafto said he confirmed there was a Nathaniel Leighton born in Falmouth who became a physician in New York and died in 1899, so the crypt was probably not for him. But Shafto said it was certainly possible there were other Nathaniel Leightons.

“The name probably goes back,” he said.

A staircase leading down into the sealed crypt would have been open before, Shafto said, and the chamber would have been sealed by a door.

“It’s not a root cellar, it’s not for defense,” Shafto said. “It’s not a bomb shelter. … It’s a grave for multiple people.”

But there are no caskets or any signs of bodies in the crypt.

More modern crypts are built above ground and have the caskets built into the structure. This crypt was built into the ground, indicating it is older. As the bodies and caskets accumulated in the crypt, Shafto said it was likely they were moved to make room for more family members.

“No one knows where (the bodies went),” Shafto said, adding it is possible the area surrounding the crypt was a cemetery, although it’s too weathered to determine if that’s so. There are cut stones in the area that could have been grave markers, he said.

He also said it is possible the bodies were later buried at a nearby cemetery known as the Leighton Cemetery, which is about a mile up the road. There are a several such private cemeteries scattered across town, dating back hundreds of years.

“It’s a hell of a place to be buried,” Shafto said, because the crypt sits on a bluff overlooking a stream. While it is wooded now, Shafto said the land was likely open and cleared when the crypt was built.

Shafto said the crypt was filled with sand in the mid-20th century to keep children from playing in it. It was eventually dug out, presumably by the children who wanted to keep playing in it, which is probably when it was sealed with a large rock.

At one point, Shafto said, it also could have been used for storing bootleg alcohol during Prohibition.

Shafto said while it would be nice to restore the crypt, which is on town-owned conservation land, there are no plans to do so. He asked people to be respectful of the crypt, and by extension the lives of those associated with it.