Footwear outsole and article of footwear

Footwear outsoles and articles of footwear wherein the outsole includes an elongated lower outsole layer having: a lower surface for contact with the ground in use; an upper surface, a plurality of protrusions extending in a direction at least upward and away from the lower surface of the elongated lower portion of the outer bottom layer; and a first plurality of elastically deformable projections disposed at the lower surface and extending laterally between adjacent ones of the plurality of projections; wherein a plurality of voids are defined between adjacent protrusions and a first projection extending between the adjacent protrusions, and wherein each of the first plurality of protrusions has an upper portion, and the upper portions of the protrusions collectively define the upper surface of the elongated lower outsole layer; and an elastically deformable elongated upper outer sole layer supported by an upper surface of the outer sole layer and arranged to cover the voids to form a plurality of cavities.