New England's 'Mystery Stone'

Boisvert suggested the holes were drilled by power tools, perhaps from the 19th or 20th centuries. "What we did not see was variations that would be consistent with something that was several hundred years old," he said.

The analysis, which included comments from geologist Eugene Boudette, concluded that the stone is a type of quartzite, derived from sandstone, or mylonite, a fine-grained, laminated rock formed by the shifting of rock layers along faults. The rock type was not familiar to New Hampshire, but the state could not be ruled out as the source, Boudette said.

Boisvert said to his knowledge, the stone is unique. "That makes it very hard to figure out where it fits," he said.

One problem is the story of the stone's discovery is fuzzy, he said.

"You couldn't be certain exactly what kind of context it came from. There's a lot of ambiguity there ... it's very difficult to evaluate it," he said. "The context of the discovery is sometimes more important than the item itself."

For example, Boisvert said, if the item had been something used by a fraternal order that has its own secrets and mysteries, "that means the information doesn't get out very well, does it? The information may have been available at one point, but it's really no longer available to us. Who knows?"

Wesley Balla, the society's director of collections and exhibitions, said one avenue to explore might be looking for similar symbols. And, "there's also always the hope that there might be something more in either newspaper or manuscript form that might discuss the contents," he said.

Balla said the discovery seems to reflect on the way artifacts were treated in the 19th century. The focus was more on the object itself, not on details such as how deep the soil was where it was found, if anything was found near it, or how far it was from the lake.

"All of that is lost," he said.