Sedimentological and chronostratigraphic studies of the coastal plain sediments of the Black Sea near the Sakarya River (Turkey) and seismic-stratigraphic survey of the shelf sediments off this river's mouth were carried out. The results indicate that just prior to its flooding by the Mediterranean waters at about 7200 yr up, the Black Sea was a fresh water lake, emptying its waters into the Sea of Marmara. The water level of this lake was about 18 m lower than the present sea level, but above the -35 m sill depth of the Bosphorus. This finding contradicts with Ryan et al.'s (1997a,b) hypothesis: that the Black Sea 'lake' water level was more than 100 m below the sill depth of the Bosphorus and that the drowning of the Black Sea shelf at 7150 yr sp was abrupt. (C) 2001 Elsevier Science B.V. All rights reserved.