Three major pre-Quaternary glaciations have been recognised on King George Island. South Shetland Islands (West Antarctica). The oldest is the Melville Glaciation evidence by fossiferous glaciomarine sediments. Presence of numerous belemnites and Cretaceous calcareous nannoplankton suggested at first a late Cretaceous age. However three is an increasing evidence that these Cretaceous fossils are recycled and occur in late Tertiary (?Miocene) strata. Two glaciations separated with an interglacial have been recognised in a thick Pliocene sequence of laves and sediments. The older Polonez Glaciation is represented by continental-type tillites succeeded by glaciomarine sediments with Chlamys anderssoni fauna. Acidic volcanic activity, coarse-clastic sedimentation and subaerial erosion characterise a mid-Pliocene Wesele Interglacial succeeding the Polonez Glaciation. Andesitic laves and lahars cut by glacially eroded valleys with strongly diagenesized tillites represent the youngest, late-Pliocene Legru Glaciation.