There was something inside — a dark, odd-looking, egg-shaped stone with a variety of carvings, including a face, teepee, ear of corn and starlike circles.
And there were many questions: Who made the stone and why? How old was it? How was it carved?
To date, no one has been able to say for sure, and the item has come to be known as the "Mystery Stone." Seneca Ladd, a local businessman who hired the workers, was credited with the discovery.
"As Mr. Ladd is quite a naturalist, and has already an extensive private collection of relics and specimens, he was delighted with the new discovery, and exhibited and explained the really remarkable relic with an enthusiasm which only the genuine student can feel," an article in The American Naturalist said that November.
Ladd died in 1892, and in 1927, one of his daughters donated the stone to the New Hampshire Historical Society. The stone, surrounded by mirrors showing off its symbols, is on display at the Museum of New Hampshire History, where it was last exhibited in 1996.
All the symbols on the 4-inch-long, 2½-inch-thick stone are open to interpretation. On one side, it has what looks like inverted arrows, a moon, some dots and a spiral. Another side shows the ear of corn and a depressed circle with three figures, one of which looks like a deer's leg.
The American Naturalist suggested that the stone "commemorates a treaty between two tribes." Others have guessed the stone is Celtic or Inuit. A letter to the historical society in 1931 suggested it was a "thunderstone," which, the writer said, "always present the appearance of having been machined or hand-worked: frequently they come from deep in the earth, embedded in lumps of clay, or even surrounded by solid rock or coral."
Another curious detail is that there are holes bored in both ends of the stone, with different size bits. Each bore is straight, not tapered. Scratches in the lower bore suggest it was placed on a metal shaft and removed several times, according to an analysis done by state officials in 1994.
"I've seen a number of holes bored in stone with technology that you would associate with prehistoric North America," said Richard Boisvert, state archaeologist. "There's a certain amount of unevenness ... and this hole was extremely regular throughout."