Abstract: According to the depicted embodiment, the novel Floor Mat is formed of a substantially planar sheet having a first portion for overlying a firewall, and a second portion for overlying a level floor, both portions having raised ribs. The ribs of the first portion extend generally diagonally thereacross, with an intervening, center channel, devoid of ribs, through which particulate matter is induced to flow--toward the second portion. The latter portion has a multiplicity of the aforesaid ribs, the same extending in spaced apart disposition, parallel with the sides of the Mat. A multiplicity of apertures are formed in the sheet, interveningly between the multiplicity of parallel ribs. However, immediately adjacent to the apertures, the ribs are relieved, to allow particulate matter to flow to the apertures. In a center portion of the floor-overlying portion of the Mat, immediately adjacent to the apertures, the ribs are bridged across, by low wall members.