The area of the Middle and Upper Yenisei is one of the most important concentrations of Paleolithic sites in Northern Asia. More than 200 localities, belonging to various stages of the Paleolithic, are now known. The initial phase of the Late Paleolithic is represented by Malaya Syiya, which is dated to approximately 34,000–33,000 B.P. The middle phase of the Late Paleolithic is marked by the blade industries of Early Sartan age (24,000–18,000 B.P.), as at Shlenka, Tarachikha, Ui I, and elsewhere. At 18,000–16,000 B.P., these were replaced by the Final Paleolithic Afontova and Kokorevo cultures, although some of the earlier blade industries continued into this period (Golubaya I).