Plum Island is a barrier island located off the northeast coast of Massachusetts, north of Cape Ann, in the United States. It is approximately in length. The island is named for the wild beach plum shrubs that grow on its dunes, but is also famous for the purple sands at high tide, which get their color from tiny crystals of pink pyrope garnet. It is located in parts of four municipalities in Essex County. From north to south they are the city of Newburyport, and the towns of Newbury, Rowley, and Ipswich. History Captain John Smith Plum Island appears as an unnamed island as early as Captain John Smith's map of New England. Various scholars have speculated on the nature of the earlier accounts of European explorers in the New World, with particular focus on the latter's surveys of the coastlines of Massachusetts, but Smith's account identifies Plum Island. He describes a harbor at "Angoam" (elsewhere "Aggawom", the Anglicised Native American name for the native village that preceded Ipswich, Massachusetts, and was destroyed by smallpox) as having "many sands" at its entrance. Before it was an island: On the east is an Ile two or three leagues in length; the one halfe, plain morish grass fit for pasture, with many faire high groves of mulberry trees gardens; and there is also Oaks, Pines and other woods to make this place an excellent habitation, being a good and safe harbor. "Morish" is now "marsh", and the high gardens of "mulberry" trees may be beach plum, which prefers the crowns of the dunes, although today can be seen on only a few. The map shows an imaginary English town (the insertion of Charles I of England) of the then-future "South Hampton", about where Newbury is. The Hampton suggestions were later put to use, but farther north. The Mason grant A grant in 1621 by the Plymouth Council for New England, acting under a charter from James I of England (not then reigning) to colonize New England, deeded the land between the "Naumkeag" and Merrimack rivers to Captain John Mason. The island was to be named the Isle of Mason. Mason, then governor of Newfoundland, never acted on the grant. It was later included in a similar grant to the Massachusetts Bay Colony; nevertheless, in 1681 the heirs of John Mason petitioned the General Court of Massachusetts for possession of the grant, now