Strata of mica slate, argellaceous, and chlorite slates, and limestones, alternate. Construction material like granite, gneisses, slates tiles, and limestone, quartzite is found around the town. Grey marmorifere stone, pebbles of the Adour, bricks and slates. It is formed with granites, crystalline slates, and sandstones. Usually a thatched roof was turned into one of slates or tiles. Slates and reeds were usually used for roofing. Writing slates and blackboards have been used for at least a millennium. The bedrock of the Upland of consists primarily of sandstones and slates. The traditional thatched roof was replaced by sturdier Welsh slates. Mini tablets are smaller and weigh less than slates, with typical screen sizes between . There were further expenses, such as those for roof boards and slates. Pencils will write underwater on permatrace, plastic dive slates, or matt laminated paper. Other varieties of foliated rock include slates, phyllites, and mylonite. The whole house has a roof of Welsh slates. Mississippi put up two distinct slates, one of loyalists and one of unpledged electors.