I have often seen this in Mediterranean material from different contexts. When the wood is identifiable it is usually olive and I have attributed it to the intense heat generated by the oily wood. I am interested to hear of the possibility of charcoal used as fuel or reburning of wood in a hearth. I am teaching palaeoethnotobtany this semester so the students and I may try some experiments along these lines. Sincerely, Julie -- Julie Hansen Chair Department of Archaeology Boston University 675 Commonwealth Ave. Boston, MA 02215 (617) 353-3415 (office) 353-2637 (direct/voicemail) fax (617) 353-6800 e-mail [log in to unmask]