Ground Trace

This spell allows its caster to follow the direction and discern the extent of unseen buried roots, watercourses, tunnels, drains, pipes, passages, and even underground rooms – so long as some part of the feature (or something connected to it, such as a swill-pit joined to a drain or a tree coupled to its roots) is visible above the surface and can be seen directly by the caster before or during the casting of the ground trace spell. The trace ends when the feature passes below a mile underground or the spell expires.

Only the uppermost layer of multilevel underground features is revealed by the magic. However, the caster is made aware of branching and side passages and can often guess at more than the spell reveals. (For instance, if a tunnel splits and one passage descends and then crosses under the other, that deeper passage could not be followed as it went under the uppermost passage, but it would be apparent again the moment it emerged on the other side.) Although general depth, direction, and size are apparent to a caster looking ahead, full knowledge can be gained only by someone standing directly on the earth above the feature (that is, the presence of water blocks the sight afforded by this spell). The extent of features that can be learned is therefore determined by the caster's movement rate, freedom to move, the terrain, and the availability of marker stakes or something similar – although this spell is most commonly used to decide where to dig a shaft or intercepting passage.

The material components are a hair from the caster's body and a piece of string, cord, or thread.