… into blocks or slabs of a rectangular (including square) shape. …
Explanatory notes
… into blocks or slabs of a rectangular (including square) shape. Slate, which splits readily into thin sheets, is … further worked than described above, e.g., cut or sawn to shapes other than rectangular (including square), ground, … (b) Roofing, facing and damp course slates, even if shaped or processed as specified in the text of this …