Composite sheet

A composite sheet comprising a substantially flat lower fibrous sheet and an upper fibrous sheet bonded to the lower fibrous sheet, the upper fibrous sheet being three-dimensionally textured with a number of projections and a number of depression each of which is located between every adjacent two of the projections,

• the projections and the depressions alternating in a first direction of the composite sheet and in a second direction perpendicular to the first direction,
• the projections each having a pair of opposing first walls parallel to the first direction, a pair of opposing second walls parallel to the second direction, and a top plane connected to the upper edge of each first wall and the upper edge of each second wall, and
• the basis weight of each first wall being different from that of each second wall;
• wherein the projections and the depressions are arranged in a staggered pattern in which the projections and the depressions alternating in a line extending in the first direction of the composite sheet are out of alignment with the projections and the depressions of the adjacent lines by half the pitch;
• wherein the projections are hollow;
• and
• wherein individual depressions partly adjoin at least one other depression.