Slabs are also manufactured, and, being readily cut, planed, dressed and enamelled, are used for chimney pieces, billiard tables, wall linings, cisterns, paving, tomb-stones, ridge rolls, electrical switch-boards and various other architectural and industrial purposes.
In the last case they consist of any number of hollow cylindrical pillars, vertical or raking, turned and planed at the ends and united by a projection or socket and by flanges and bolts.
The peculiar configuration of thr~ ridges may be apprehended as follows: The pattern of the folded ~trata on the low-lying Cretaceous peneplain must have resembled the pattern of the curved grain of wood on a planed board.
The shutters must be planed, and coated with a mixture of soap and oil, so as to come away easily after the concrete is set.
The new town on the right bank is therefore a centre of the timber export trade, this place being the principal port in Norway for the export of pit-props, planed boards, and other varieties of timber.