The silver one shilling coin was made in Boston in 1652, and is one of about 40 known to still exist, a Rhode Island coin expert says
Counterfeit diagnostics
ANS Digital Library: Mark Newby's St. Patrick coinage
English silver coin dated at more than 500 years old discovered at
Rare coin made in Colonial New England could fetch $300,000
Daniel Frank Sedwick, LLC: Treasure, World, U.S. Coin and Paper
Ancient Coins
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Rare silver coin made in Colonial New England could fetch $300,000
Buying and Selling Rare Coins at Northeast Numismatics
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Coins and Currency : An Historical Encyclopedia, 2d Ed [1 ed
Buying and Selling Rare Coins at Northeast Numismatics