Sedimentary structure consisting of a series of relatively small, alternating, interlocked, toothlike columns of stone; it is common in limestone , marble , and similar rock.
The individual columns never appear singly but occur as a succession of interpenetrations that in cross section make a zigzag suture across the face of the stone. Most geologists believe that they are of secondary origin; that is, they result from differential chemical solution as groundwater circulates along a parting in hardened rock.