Kalina, I admire your self-confidence. However, Galileo is out of place here - your problem is simple basics of sedimentary geology. The rocks are there, they have stayed for more than 20 Ma, and will stay probably even for longer! In exchange to your lesson of self-criticizm, I am inviting you to make together the small excursion to Rila and Padala, for to show you the sandstone interbeds with coalefied plant debris, and the coal lenses described by Bonchev and Konyarov. Find me next week in my office for to fix the details - I'll arrange the transport. Cheers, Ivan Ivan Zagorchev Geological Institute, Bulgarian Academy of Sciences Acad. G. Bonchev Street bldg. 24, 1113 Sofia fax (00359-2) 724638 E-mail [log in to unmask] %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%