The geological structure of Poland has been shaped by the continental collision of Europe and Africa over the past 60 million years and, more recently, by the Quaternary glaciations of northern Europe. Both processes shaped the Sudetes and the Carpathian Mountains. The moraine landscape of northern Poland contains soils made up mostly of sand or loam, while the ice age river valleys of the south often contain loess. The Polish Jura, the Pieniny, and the Western Tatras consist of limestone, whereas the High Tatras, the Beskids, and the Karkonosze mountain ranges are made up mainly of granite and basalts. The Polish Jura Chain has some of the oldest rock formations on the continent of Europe.