This term was first used by R. Thiessen in 1930 referring to the attritus of ordinary humic coal, which is ordinarily composed largely of transparent humic matter, with spores, cuticles, resins, and opaque matter in minor proportions. Translucent attritus consists of the complex residual organic matter, exclusive of anthraxylon, in bituminous lower rank coal that transmits light in thin section. The following macerals of the Stopes-Heerlen nomenclature are included in translucent attritus: vitrinite less than 14 mu m thick; sporinite; cutinite; alginite; resinite; and those parts of semifusinite, micrinite, and sclerotinite that are weakly reflecting, that is semitranslucent. Translucent attritus is a collective term and is not comparable with any of the microlithotypes of the European system of nomenclature.