WESTPORT ISLAND — A safe stolen from the Colonial Pemaquid historic site in Bristol has been found about 10 miles away by a 9-year-old boy playing on a riverbank.

The safe was stolen Aug. 18 or 19.

It was found last weekend in a cove on the Sheepscot River on Westport Island by Garrett Pinkham.

Garrett’s mother, Alice Cromwell, tells The Times Record the safe contained cash, a few rare coins, bank notes and 2014 state park passes.

John Bott, spokesman for the state Department of Agriculture, Conservation and Fishery, said Wednesday the safe had been used to store cash transactions.

Just how the safe made it so far remains a mystery. It’s 10 miles as the crow flies, but a nearly 30-mile drive.

The burglary remains under investigation.