Oolite

Olite or Oolite - granular limestone.
Onager - Roman name for a Mangonel, literally a "wild ass". A light stone throwing engine, powered by a skein of twisted rope.
Open joint - wide space between faces of stones.

- a honey coloured oolite limestone, good for dressing and carving, but useless for paving, available from quarries in Somerset and Wiltshire.

This is a high quality dimension stone originating from the Isle of Portland in Dorset. It is a strong uniform stone (Jurassic oolite) without internal laminations.
Pre-cast concrete ...

See also: System, Brick, Ground, Limestone, Staircase