If the top or apex of the lode in its longitudinal course extends beyond the exterior lines of the claim at any point on the surface or as extended vertically downward, such lode may not be followed in its longitudinal course beyond the point where it is intersected by the exterior.

Source: PolC 1877, ch 31, § 10; CL 1887, § 2006; RPolC 1903, § 2541; RC 1919, § 8735; SDC 1939, § 42.0112.