Stone Slab
Stone Slab and Stone Slab Fragments are items found only in the original version of Link's Awakening.
Stone Slabs
Stone Slabs are tablets that hang on dungeon walls. Each Slab is missing a piece, which is located somewhere in the respective dungeon. When the missing piece of stone is put into the slot of the slab, the tablet could then be read by Link. All of them provided a clue to a nearby challenge.
The stone Slabs were later replaced by Owl Statues when Link's Awakening DX was released.
Stone Slab Fragments
There is one 'Stone Slab Fragment found in each of the eight Dungeons on Koholint island. When attached to a Stone Slab, it would give Link a hint, either about a puzzle, a monster, or a dungeon boss or mini-boss.
The Stone Slab Fragment was proceeded by the Stone Beak when Link's Awakening DX was released.