In the commoner buildings these may be of rubble; but they are more frequently of cut stone even in rubble walling They are generally formed with reveals, as explained at page 10, the thickness of stone in front of the check, or sinking for the frame, varying from 6 to 12 inches.
Fig. 142. Stone Jamb with Reveal.
2 Throating is cutting a groove or throat on the under side of that part of a stone which projects over a wall, in order that the water trickling over the face of the stone may be stopped before it reaches the wall.
3 Sc. Inbonds and Outbonds.
In other cases the jambs each consist of one long stone on end, the height of the opening, with the architrave worked upon it.