Why is Cthulhu on this 300-year-old gravestone?

Nor is Duxbury free of its own oddities. Duxbury does not feature in any of Lovecraft’s fiction; Arkham is based on Salem, Innsmouth is based on a combination of Ipswich and Gloucester, and Dunwich is based on Athol. But Duxbury was no stranger to sea serpents, even in Wiswall’s day. The English writer John Josselyn’s An Account of Two Voyages to New-England (1674) described the 1639 sighting of a sea serpent off Cape Anne, north of Duxbury, which sparked a rash of sea-serpent sightings along the Massachusetts coast, including Duxbury. And in 1857 Henry Thoreau wrote in his journal that Daniel Webster had seen a sea-serpent off the coast of Duxbury — via io9