Thickness Of Layers

In selecting sandstone for undercut work or for carving, care must be taken that the layers are thick; and it is of course important that stones should rest in most cases (see p. 37, Part I.) on their natural beds.

Uses

The hardest and best sandstones are used for important ashlar work; those of the finest and closest grain for carving; rougher qualities for rubble; the well-bedded varieties for flags.

"Some of the harder sandstones are used for sets, and also for road metal, but they are inferior to the tougher materials, and roads metalled with them are muddy in wet, and very dusty in dry weather." l

1Wray,

Principal Varieties In Common Use

A lew of the best known sandstones will now be described, after which a list will be given of some of the principal quarries in Great Britain and Ireland.