Anguilla Liberty $ countermarked on Mexico

This is the most common (5,987 struck) of this series of Provisional Government Coinage of 1967. This is when the island tried, unsuccessfully, to separate from the union with St. Kitts & Nevis imposed by the British. By 1969 the British landed paratroopers and policemen on the island to restore order. By 1976 Anguilla was declared a self-governing dependent territory. The unusual history of how these special issues came about has finally been revealed in Krause publications "World Coin News" for Jan 2015.
ANGUILLA: British Territory, AR liberty dollar, 1967, KM-X2, Referendum on Anguilla's Secession, counterstamped on Mexico silver 5 peso 1948, EF. These counterstamped coins, "Anguilla Liberty Dollar, July 11, 1967 ", were made by Scott Newhall, then-editor of the San Francisco Chronicle. Always on the lookout for a zany antic to splash across the editorial pages of the Chronicle, Newhall embraced the so-called Anguillan revolution of 1967. To facilitate commerce for the revolutionaries, Newhall, an avid coin collector, took 11,600 dollar-sized silver coins and counterstamped them in the basement of the Chronicle building in San Francisco. The idea was Newhall would be recompensed for his actual costs, and the new Anguillan government would sell the coins to collectors at a surcharge and keep the profits. It bombed. Just 2,000 to 3,000 were put into commerce, and Newhall was stuck with the balance of the defaced coins, which he eventually sold for the melt price of silver. Many more were melted in the following years and they are now becoming scarce.
For more details, see A Referendum, a Newspaper Editor & a Coin – The Story of the “Anguilla Liberty Dollar”, Jay Turner, PCGS, 9 April 2020..at this: https://www.pcgs.com/news/story-of-anguilla-liberty-dollar
See also: https://scvhistory.com/scvhistory/lw2422.htm