Abstract: An elongated tape for marking underground lines having a cross-woven scrim formed by a first plurality of elongated plastic fibers disposed parallel to the axis of elongation of the tape and a second plurality of elongated fibers disposed normal to the fibers of the first plurality. Preferably, the tensile strength of the second plurality of fibers exceeding the tensile strength of the first plurality of fibers. The scrim is coated with a layer of plastic to form a surface, and a sign is disposed on the surface. If the tape while buried encounters a digger, it tends to break transversely rather than along the axis of elongation leaving the sign legible. In one embodiment, a layer of electrically conducting foil is disposed on one side of the scrim.