In mining law when part of a vein on the dip, lies outside of the side lines of the location within whose surface lines the apex of the vein appears, and not to any part of such vein, either the outcrop or the segments on the dip thereof, which lie wholly within planes drawn downwards coincident with the surface boundaries of the location. The extralateral rights of the locator of a lode mining claim do not attach until after, in pursuit of his vein on its dip, he crosses the side lines of his location.