Updated

The contents of a 19th-century time capsule uncovered in Plymouth, Mass. continue to be shrouded in mystery.

Roughly the size of a lunchbox, the time capsule was placed beneath the granite staircase of Coles Hill when it was built in 1881. A national historic landmark, Coles Hill contains the first cemetery used by the Mayflower pilgrims after their arrival in Plymouth in 1620.

“The box was uncovered in 1930 during repairs to the lower flight of solid granite steps,” explained Donna Curtin, Executive Director of Plymouth’s Pilgrim Hall Museum, in an email to Fox News. “They opened the box, looked at the contents, added a few items from their own time, then sealed it up again and put it back under the corner of the heavy granite slab where it had been found.”

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Curtin explained that, unfortunately, when the capsule was re-interred, the box was placed on a porous cement pedestal rather than simply being placed back in the ground. “As the cement slowly eroded at one corner, the weight of the staircase eventually crushed the top of the box and ripped open gaps at the sides,” she said. “Right now, the box can’t be opened due to the condition of the lid.”

The Milford Daily News reports that a construction crew discovered the box when they were renovating the staircase last week.

“It’s evident that water did get inside and has definitely turned some items to mush,” said Curtin. “We remain hopeful that other items remain in the box that may be recoverable- it’s surprisingly heavy.”

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The next stage for researchers is to carefully examine the box, work out how best to open it and then have a conservator examine the contents, according to Curtin. “Even if items are badly damaged, a trained conservator can often stabilize and treat an object to make it recognizable,” she told Fox News. "What did the people of Plymouth in 1881 and in 1930 want to share with Americans of the future, with us? Pilgrim Hall Museum hopes to uncover some answers."

However, it may be a few weeks before additional information on the mysterious time capsule is available.

Follow James Rogers on Twitter @jamesjrogers