What beach you found it on would be very helpful. I suggest looking up Coin Beach in Delaware. There are loads of finds that look just like that. I wouldn't trust my fuzzy memory, but I think they were from one of the British Isles that keep washing up from a shipwreck nearby (the second photo from a post of finds on Coin Beach Delaware by Smokeythecat who is a member here, I will remove if he requests it):
"Harry Wenzel did extensive historical research on the Faithful Steward shipwreck off the Indian River Inlet in 1785, which left 180 passengers and crew dead and dumped 400 barrels of copper coins into the water, creating 'Coin Beach,' where the coins have often washed up over the years.
In the category of “the truth is often stranger than fiction,” author Harry Wenzel brings to readers his second non-fiction shipwreck story, “The Ship Faithful Steward: A Story of Scots-Irish, English, and Irish Migration to Pennsylvania.” It could well be a page-turner for this winter’s reading, and the book is due to be sold in Lewes — where much of Wenzel’s research at the Lewes Historical Society was conducted — starting right after Thanksgiving."