In mining law. The line of declination of strata; the angle which measures thedeviation of a mineralized vein or lode from the vertical plane; the slope or slant of avein, away from the perpendicular, as It goes downward into the earth ; distinguishedfrom the “strike” of the vein, which is its extension in the horizontal plane, or itslengthwise trend or course with reference to the points of the compass. King v. MiningCo., 9 Mont. 543, 24 Pac. 200; Duggan v. Da- vey, 4 Dak. 110, 26 N. W. 887.