Acadian settlements in the past varied in size, style, and structure among the four major environmental zones. Settlements included isolated houses, small farms, towns, ranches, and families living on houseboats. Population relocations, the arrival of non-Cajuns, and changes in economic activities have all produced changes in settlement patterns. In recent years, there has been a marked trend to settlement in towns and cities through migration from the rural areas. The Acadian cottage, a small, nearly square dwelling with a covered front porch and high-pitched roof, was a distintively Cajun house type in the 1800s. It was raised a few feet above the ground and constructed from cypress wood and infilled with clay and moss. Some later styles of dwellings were elaborations on the basic style, though all have now been replaced by modern-style homes made from mass-produced materials.