Both official and individual, architecture is a very visible expression of local culture. When you think of typical Norman houses you probably picture half-timbered cottages or farms, with thatched roofs and irises growing along the rooftop. In many ways you will be right, for until the industrial revolution people built their homes from the materials available nearby, and in much of Normandy the local materials were wood, straw and thatch. Dressed stone was expensive, and in short supply, but rocks and pebbles cleared from fields were never lacking. So in areas such as the Auge country, the Marais Vernier wetlands, in the Eure region and in the west, timber-framed buldings abound, with local differences in structure and half-timbering, constructed on base courses of undressed local stone or bricks. In the north, and to the east closer to Paris, where stone and good bricks were more readily available, traditional building styles make more use of those materials, and less of wood, with tiled roofs instead of thatch.