NANTUCKET, an island, county, and town of the United States, forming (since 1693) part of Massachusetts. The island, with an area of about 50 square miles, lies within the 10-fathom line, but is separated from the mainland by Nantucket Sound, which measures from 25 to 30 miles in breadth, and has a general depth of from 5 to 8 fathoms. With the exception of a few inconsiderable hills, the surface for the most part consists of open, breezy, and now almost treeless downs. The soil is generally sandy, but affords in some places good pasture. On the north or landward side of the island there is a large lagoon-like harbour formed by a long narrow tongue of land—the Coatue Beach—which, curving north-west, runs out into Great Point, the end of which is marked by a white lighthouse tower in 41° 23' 24" N. lat. and 70° 2' 24" W. long. Within the harbour the depth at low water is about 12 or 14 feet, but on the bar it is only between 6 and 7. The western end of the island shelves out in a broad submarine platform (Tuckernuck Bank), which supports the two considerable islands of Tuckernuck and Muskeget, both included in the county. Nantucket post-village, the principal settlement, lies at the south-west end of the harbour, —a quiet place, but beginning to attract attention as a summer residence. A library and museum are maintained in the Athenøeum building....