Many traditional Scottish buildings have roofs that are covered with local slate or stone. The relatively small and thick Scottish slates were produced in a variety of lengths and widths, and laid with the largest slates at the base of the roof, with the smaller ones at the top. This method was introduced for purely economic reasons. It made best use of all the material produced and resulted in the unique roofscapes we enjoy today. Each roof slope bears a fingerprint of the quarry that supplied the material, with the pattern of diminishing courses, and the colour and textures all being highly distinctive. Once these characteristics have been identified it is possible to recognise the same traits in any neighbouring buildings roofed with material from the same source.