"Deformation of plastic kaolinite-illite clay caused alignment of authigenic prisms of rutile and tourmaline on surfaces produced by parallelism of the basal pinacoids of the clay-minerals. An a-lineation appeared in the outer layers of an extruded cylinder but a b-lineation in those of a cylinder formed by rolling. A b-lineation occurred at the periphery of a circular disc made by spreading. Localized tensional failures, cognate with ac joints, accompanied the b-lineations which were in directions of elongation. The orienting movements were thought to occur in the water-films separating the clay-flakes, but the mechanisms which produce a-and b-lineations are presumably identical. Thus it can be argued that the a-lineation also follows a direction of elongation."