This region is historically and collectively known by naturalists as the Outer Lands. Cape Cod incorporates all of Barnstable County, which comprises 15 towns: Bourne, Sandwich, Falmouth, Mashpee, Barnstable, Yarmouth, Harwich, Dennis, Brewster, Chatham, Orleans, Eastham, Wellfleet, Truro, and Provincetown. Each of these towns include a number of villages; see Barnstable County for a complete list. Barnstable, the most populated municipality on Cape Cod, is the only one to have adopted a city form of government, whose legislative body is an elected 13-member council. However, like other smaller Massachusetts cities, Barnstable retained its "Town of Barnstable" moniker. All of the other towns elect a 5-member Board of Selectmen as the executive policy-setting board, and utilize Town Meetings as their legislative body. To the south of Cape Cod lie Nantucket Sound; Nantucket and Martha's Vineyard, both large islands; and the mostly privately owned Elizabeth Islands. For most of the 18th, 19th, and 20th centuries, Cape Cod was considered to consist of three sections (see map):  The terms "Upper Cape" and "Lower Cape", and references to traveling "up Cape" or "down Cape" have long been a source of confusion for the uninitiated Cape Cod visitor, who, mistakenly associating "up" with "north", might get turned around by passages such as these from 1920:   There are many theories to explain the apparent paradox. One is that the terms derive from early nautical navigation. When one traveled to the east, one went down the longitudinal scale (toward zero at Greenwich, England). Additionally, prevailing fair weather winds (generally out of the southwest) have been used as the basis for directional descriptions by European settlers and their descendants in eastern North America. That is, one would be traveling "down [wind]" to the east with a westerly wind at one's back. To this day, on nearby Martha's Vineyard, "Up Island" is the western section and "Down Island" is to the east. The arrival of the railroad during the nineteenth century reinforced the "up/down" concept, as train schedules between Boston and Cape Cod always showed Boston at the top – the timetable for trains headed onto the Cape would be read from the top down, and those of returning trains would be read from the bottom up. Provincetown, therefore, despite being the Cape's northernmost town, was the furthest "down" that one could travel.