Dutch barn is the name given to markedly different types of barns in the United States and Canada, and in the United Kingdom. In the United States, Dutch barns (a. k. a. New World Dutch barns) represent the oldest and rarest types of barns. There are relatively few—probably fewer than 600—of these barns still intact. Common features of these barns include a core structure composed of a steep gabled roof, supported by purlin plates and anchor beam posts, the floor and stone piers below. Little of the weight is supported by the curtain wall, which could be removed without affecting the stability of the structure. Large beams of pine or oak bridge the center aisle for animals to provide room for threshing. Entry was through paired doors on the gable ends with a pent roof over them, and smaller animal doors at the corners of the same elevations. The Dutch Barn has a square profile, unlike the more rectangular English or German barns. In the United Kingdom a structure called a Dutch barn is a relatively recent agricultural development meant specifically for hay and straw storage; most examples were built from the 19th century. British Dutch barns represent a type of pole barn in common use today. Design styles range from fixed roof to adjustable roof; some Dutch barns have honeycombed brick walls, which provide ventilation and are decorative as well. Still other British Dutch barns may be found with no walls at all, much like American pole barns.