Extradimensional Detection

When extradimensional detection is cast, the priest detects the existence of any extradimensional spaces or pockets in a path 10 feet wide and 60 feet long in the direction he is facing. The priest may turn, scanning a 60° arc each round, or may move slowly while the spell is in effect to change the sweep of the detection.
Extradimensional spaces include those created by spells such as Rope Trick and those contained within such items as bags of holding and portable holes. The priest does not automatically know the size of the space or its source.
This spell detects interplanar gates and the "gate" opened by the spell Dimensional Folding. The spell can be blocked by a stone wall of one foot thickness or more, a one-inch thickness of solid metal, or one yard or more of solid wood.

[Tome of Magic]

Sphere: Numbers, Divination
(Divination)
Level: 3

Range: 0
Components: V, S
Duration: 1 round/level
Casting Time: 3
Area of Effect: One 10'-wide path, 60 feet long
Saving Throw: None