ROSLYN, LONG ISLAND (CBSNewYork) — Within the walls of the historic Roslyn Grist Mill, circa 1715, a crew working to restore the landmark stumbled upon a time capsule that’s more than a century old.

“They had four vintage coins also in it,” said Howard Kroplick of the Roslyn Landmark Society.

Inside a weathered half-pint milk bottle were four rare coins, including a Civil War money piece and a Haitian centime, and two letters. One in English from proud builder, poet William Cullen Bryant’s grandson. The other, in Italian, from Romolo Capparrelli, who invented the planking-style concrete roof, without a blueprint, architect or engineer.

“I am Romolo Caparelli. I worked on the grist mill… Please remember me,” reads one letter.

Kroplick and Jennifer Lister of the Roslyn Landmark Society say the community is giddy.

“To find such a piece of history is just really a treasure,” said Lister in an interview with CBS2’s Jennifer McLogan.

MORE: Nassau County Moves Full Speed Ahead With Restoration Of 300-Year-Old Roslyn Grist Mill

The water powered flour mill was the middle of commerce 300 years ago.

“This was the economic center of the village of Roslyn,” said Kroplick.

The mill fell into disrepair and it took a village to revive it. CBS2 was there in January when the town, county and state matched funding.

Even George Washington was a fan. He mentioned the mill in his diary in 1790.

It will soon be open as a museum.

“We should put our own little message in a bottle when we get this structure back together,” said Lister.

Once the restoration is complete, the letters, the messages, the bottle and the coins will be on display for future generations.

History preserved.

MORE FROM CBS NEW YORK: