Dispersed organic matter of plant origin from three sites of the Middle America Trench transect was investigated by coal petrographic methods. Samples from the slope region are rich in lipoid and inert substances. Humic matter is predominant in the trench sediments. Reflectance measurements show that the rank of the organic matter is peat, independent of the tectonic position and age of the samples in question. A slow increase of coalification with depth is observed.

Supplement to: Wolf, Monika (1982): Coal petrological studies of sediments from Sites 496, 499, and 500, Deep Sea Drilling Project Leg 67, Middle America Trench and slope off Guatemala. In: Abouin, J; von Huene, R; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 67, 601-602