Abstract: Paleozoic formations of the Bozüyük - Söğüt (Bilecik) area are called Bozüyük metamorphites. Of the rock unitswhich comprise this formation, orthogneiss, greenschist, glaueophane schists are of ortho mica-schists are of para origin.These are formed by regional metamorphism of clay, sand, granitic intrusion products within the region.