Americans tend to think that varieties of English are more determined by region than by any other factor, such as age, ethnicity, gender and social class. The linguist Henry Smith, for instance, maintained that each region of American English is highly distinctive. Scholars who have investigated the matter have been influenced by the theory of dialect geography formulated in the 19 th century by European dialectologists. As a result, investigations have presumed the idea of long-settled and stable regions – an idea appropriate for Europe but less suitable to the more recent and fluid settlement patterns of the US. Even so, American English dialects are conventionally treated under four headings: North, Coastal South, Midland, and West. The Northern dialect stretches from New England to New York and was shaped by migration from the 17th century colonial settlements. The Coastal Southern dialect centres on the Atlantic port cities of the states of Virginia, the Carolinas and Georgia, formed in a time of plantation and ranch agriculture. The Midland dialect is spoken between North and South Midlands according to some dialectologists while others emphasize its affiliation with its neighbours and describe it as Lower North and Upper South. Finally, the Western dialect is used in the area that covers California and the Pacific Northwest.