Plate P4. Variable contribution of cell walls to the bulk of vitrinite. 4. T5859; Hole 1118A; 580.69 mbsf. Same as figure 3, but in fluorescence mode. Strongly fluorescing cell walls in telovitrinite. The thickness of the cell walls suggests that some secondary cell wall material may be present and that both types of cell wall show similar fluorescence. The color and intensity of the fluorescence is similar to that of suberinite, but the morphology is not that of cork cells (reflected light; field width = 0.22 mm; mean vitrinite reflectance = 0.27%).