A corn head assembly for a combine harvester capable of preventing or inhibiting grain from sliding off a row unit without inhibiting crop flow is disclosed. The corn head assembly is attached to a combine harvester for harvesting crop material. The corn head assembly includes a frame, a conveyor and a plurality of row units. Each row unit includes a catch plate for facingly engaging a flow of crop material and includes a facing surface having a nonplanar geometry. The nonplanar geometry is at least one of corrugations, scales, waves, chevron-shaped corrugations, weld beads, rods, and terraces.
