Nearly 120 years has passed since the first discovery of Acheulean bifaces found in the southeastern Anatolia region, and the number has greatly increased during this period. All of the bifaces were found on the surface and generally around Gaziantep, Şanlıurfa and Adıyaman (Bostancı, 1961, Bostancı, 1971, Bostancı, 1975, Çiner, 1958, Erguvanlı, 1946, Garrand, 1997, Kansu, 1964, Kökten, 1947a, Kökten, 1947b and Kökten, 1952).

Actually, due to systematic surveys carried out in the Euphrates Basin, local concentrations of Acheulean bifaces are very well known in the southeastern Anatolia region. One of the most significant factors in the increase in biface discoveries is the systematic and intensive surveys Kökten initiated in the Euphrates Basin within the scope of the Keban Dam project. It was continued by different researchers within the scope of the Karakaya, Atatürk and Birecik Dam projects (Albrecht et al., 1984, Bourguignon and Kuzucuoğlu, 1999, Kökten, 1971, Kökten, 1974, Kökten, 1976, Özdoğan, 1977 and Yalçınkaya, 1984).

The last dam built on the Euphrates was the Karkamış Dam. The archeological surveys carried out from 1998 to 2000 in the reservoir area have once again shown the richness of the Euphrates Basin (Taşkıran, 2002a, Taşkıran, 2002b, Taşkıran and Kartal, 1999 and Taşkıran and Kartal, 2001). Seventy open-air sites or discovery locations were identified during the surveys, which showed that bifaces typologically belong to the Middle or Late Acheulean period. Dızmırtaşı is a great Paleolithic open-air site presenting typical examples of the Late Acheulean period. Most of the 74 bifaces obtained from this open-air site are in amygdaloidal shapes (Fig. 2). Moreover, ovoid, cordiform and Micoquian bifaces, and partial bifaces on flakes, were also found. It is possible to state that a Late Acheulean culture characterized by trihedral picks (Fig. 3) existed in the area of the Euphrates Basin in Anatolia (Taşkıran, 2008), similar to that in northern Syria (Copeland, 2004, Hours, 1981 and Muhesen, 1985).

The other important river of the region is called the Tigris. Unfortunately, the Paleolithic potential of the Tigris Basin remained unknown until the 2000s. A great number of biface discoveries were made during a survey, which was carried out under my responsibility in the reservoir area within the scope of the Ilısu Dam project. Identified open-air sites and Acheulean bifaces showed the richness of the Tigris Basin in terms of Acheulean culture (Taşkıran, 2006, Taşkıran, 2007, Taşkıran, 2008, Taşkıran and Kartal, 2003, Taşkıran and Kartal, 2004a, Taşkıran and Kartal, 2004b, Taşkıran and Kartal, 2008, Taşkıran and Kartal, 2009, Taşkıran and Kartal, 2011 and Taşkıran et al., 2005). Most of the local discoveries up to now are from the lower and middle Paleolithic Age. The Acheulean bifaces are the most abundant among all the surface materials collected (Fig. 4). Not only the amygdaloidal bifaces of classical types, but also partial bifaces on small or big flakes are widely found. Moreover, some cleavers on flakes (Fig. 5) and a very few trihedral picks were also found. Bifaces weighing over 1 kg were found particularly in the Raman Mountain (Taşkıran and Kartal, 2004a, figs. 22 and 24).

After the Paleolithic Age surveys carried out in the Tigris Basin, Diyarbakır, Batman and Mardin provinces were also seen to be rich in terms of biface discoveries in addition to the Gaziantep, Şanlıurfa and Adıyaman provinces in the southeastern region of Anatolia. The Paleolithic Age survey at Ilısu reservoir could not be carried out within the provincial borders of Siirt. In the future, when the surveys are fully completed, it is highly possible that biface discoveries will be made in Siirt province as well in the region of the Botan stream flowing on the provincial borders. Therefore, all of the provinces of the southeastern Anatolia region, except for Şırnak, are the richest areas of Turkey in terms of biface discoveries.

Bifaces have been found in some other regions of Turkey. However, the number is very small and they are isolated discoveries. The central Anatolia region is another rich region in terms of biface discoveries. Acheulean bifaces were found during surveys that took place around Ankara in the 1940s and 1950s (Bittel, 1934, Kansu, 1939, Kansu and Ozansoy, 1952 and Kökten, 1953; and later in the 2000s Kartal, 2005). Another place where numerous bifaces have been identified is the Niğde province in the same region. It is known that many bifaces were found around the Göllüdağ Mountain during surveys that were carried out to find obsidian sources in the province (Nur Balkan-Atlı, personal communication, October 4, 2013; see also Balkan-Atlı et al., 2009). Bifaces were not only found on the surface but also from deeper stratigraphy in the Niğde province. During the archeological excavations carried out at Kaletepe Deresi 3 (KD3), bifaces made of obsidian and rhyolite were identified by stratigraphy in an Acheulean position (Slimak, 2004 and Slimak et al., 2005). It is obvious that more surveys should be carried out both in the Ankara and Niğde regions because of the strong potential for Acheulean bifaces in these provinces. Bifaces have been found in the Eskişehir (Chaput, 1941), Nevşehir (Todd and Pasquare, 1965), and Çankırı and Çorum ¹ 1

Two bifaces found in the Çorum and Çankırı provinces are present in the collections of the Prehistory Department in Ankara, but no report was made on these samples.

Bifaces are also found in the Mediterranean region both on the surface and in the stratigraphy, like the central Anatolia region. Many bifaces were found on the surface in and around Hatay province located in the eastern part of the region (Şenyürek, 1961, Şenyürek and Bostancı, 1958a and Şenyürek and Bostancı, 1958b). Hatay has a high potential for biface discoveries because it is situated on the “Levantine Corridor” in the Near East, and along the possible migration routes of the Paleolithic Age.

Furthermore, Acheulean bifaces were found in the area called KM 43 during the survey carried out in Kahramanmaraş province, which is also located at the end of the “Levantine Corridor” (Carter, 1995). Antalya, located in the West of the region, is another province where there are dense occurrences of Paleolithic Age culture. Bifaces are found in stratigraphic positions older than 400,000 BP in the Karain Cave located in this province (Kökten, 1949, Kökten, 1955 and Yalçınkaya et al., 2009). Although bifaces were not found in a wide area between Hatay and Antalya provinces, one should bear in mind that the Mediterranean region has a strategic position in terms of biface distribution in Anatolia.

The eastern Anatolia region also has potential for biface discoveries. Bifaces were found during surveys carried out by İ. Kılıç Kökten on the provincial borders of Elazığ and Tunceli as part of the Keban Dam project (Kökten, 1971, Kökten, 1974 and Kökten, 1976). Kökten also found Acheulean bifaces around Erzurum (Koşay, 1984). Another significant discovery in this region is Kars and its surroundings where basalt bifaces (Fig. 6) found by Kökten are distinctive examples (Kökten, 1942, Kökten, 1943, Kökten, 1948 and Kökten, 1953). Notably, Kars is located on one of the crucial routes used by the migration of Homo erectus out of Africa. This route also plays an important role in access to the Caucasus with a tradition of making bifacial tools.

Acheulean bifaces are much more rarely found in other regions of Turkey. For instance, while two bifaces were found in Kastamonu province (Bostancı, 1952) in the western part of the Black Sea region, only one biface was found in Samsun (Kökten, 1951), Ordu (Kökten, 1963) and Bayburt provinces (Gündüzalp, 1986) in the eastern part of the Black Sea region. Individual, or very few, bifaces were found east of the Bosphorus (Atasayan, 1941 and Jelinek, 1980), in Bursa (Dinçer, 2010) and Çanakkale in the Marmara region, in İzmir (Kansu, 1963 and Kansu, 1969) in the Aegean region and Kütahya (Efe, 1990) in the central western Anatolia region. The recent finding of a typical Micoquian biface in Afyonkarahisar also makes the Aegean region a significant location (Taşkıran and Taşkıran, 2011).

The greatest discovery in the Aegean region in recent years was of human fossil remains of H. erectus in Kocabaş, which dates back 1.2 million years (Lebatard et al., 2014). After the discovery of fossil remains of H. erectus in Kocabaş (in Denizli province), a Paleolithic survey was conducted by Dr. Kadriye Özçelik in that region in 2014. Acheulean bifaces were also found in Denizli province during this survey (Özçelik et al., 2016).

When we look at the general distribution of Acheulean bifaces in Turkey, it appears that Acheulean culture is considered to have reached Turkey via the “Levantine Corridor” through Hatay. On the other hand, our knowledge is very limited about a definite date for Acheulean culture in Anatolia, in spite of the concentrated Acheulean findings. The only information on this is presented by Minzoni-Déroche (1987) as the result of a comparison with northern Syria. In the survey around Gaziantep, the geomorphological environment where Paleolithic tools were found was taken into consideration. Quaternary terraces of the Euphrates were examined, and some bifaces were collected from conglomerates present in these terraces. The material collected from the Quaternary Fluvial II (QF II) formation was dated as late Acheulean, i.e., c. 300,000 BP, based on technical and typological features. Bifaces collected from the Quaternary Fluvial III (QF III) formation were dated as middle Acheulean, i.e., c. 700,000 BP (Minzoni-Déroche, 1987, Minzoni-Déroche, 1988 and Minzoni-Déroche, 1989). When the hypothesis of the African H. erectus migration and the dissemination of Acheulean culture into Eurasia through the “Levantine Corridor” is taken into consideration, the ages of the oldest settlements in the Near East (Bar-Yosef, 1994) such as Ubeidia (1,400,000 to 1,000,000 BP) and Gesher Benot Ya’aqov (900,000 to 680,000 BP), in addition to the dates obtained from the Euphrates terraces, seem to be reasonable.

Therefore, it is obvious that Anatolia plays a pivotal role in terms of the distribution of Acheulean culture from Africa, and it is possible to draw some routes when looking at the distribution of Acheulean culture in Turkey (Fig. 7). H. erectus groups entering Anatolia through Hatay might have followed the Mediterranean shoreline and come up to Antalya moving westward. Although there is a gap between Hatay and Antalya in terms of the discovery of Acheulean culture, it was possible for men to follow such a route and easily arrive at the Karain Cave. The journey from Antalya to Denizli may also be supported by the discovery of Kocabaş Man (H. erectus) in Denizli. The journey could have been from Antalya to Denizli or vice versa. If that is the case, and Dursunlu (Güleç et al., 1999) is thought to be the oldest discovery location in Anatolia, H. erectus could have followed a westward migration route from the North of the Taurus Mountains.

Looking at the distribution of Acheulean bifaces, one may possibly assume an alternative northward migration route via Hatay, far beyond the Taurus Mountains, reaching central Anatolia rich in obsidian sources, and then turning to the east of the Bosphorus (Fig. 7). Yet another route may also be suggested through Antalya up to the North and then via Denizli, Afyon, Kütahya, Eskişehir, Bursa and Kocaeli to the east of the Bosphorus. Unfortunately, both northwest routes have shown that no transition from Anatolia to Thrace can be assumed. No Acheulean cultural remains have been found in Thrace. Biface-making techniques cannot be found in the Yarımburgaz Cave located in this region and dating back 400,000 years BP (Kuhn et al., 1996 and Kuhn et al., 1998). Moreover, Acheulean bifaces have not been found in the Balkan Peninsula. Therefore, a transition from Anatolia to southeastern Europe, or vice versa, cannot be assumed. Although evidence is scarce, recent discoveries in the Aegean Islands suggest that there may be a possible Pleistocene land bridge between the islands (Galanidou, 2013, Galanidou et al., 2013, Kopaka and Matzanas, 2009 and Strasser et al., 2011).

Acheulean cultural remains are frequently found in the Caucasus (Lioubine, 1998; Ljubin and Bosinski, 1995). According to the location of discoveries of Acheulean bifaces in Turkey, the most probable route is from Turkey to the Caucasus. This route starts from the southeastern Anatolia region, more particularly from the Euphrates Basin, and reaches the Caucasus from the northeast for the distribution of Acheulean culture. It is highly possible that H. erectus, migrating out of Africa, followed this route to reach the Caucasus (Fig. 7).

Another issue for discussion is the “Movius Line”, which is applied to Turkey. The “Movius Line”, suggested by L. Hallam, divided Eurasia into two parts: the southern and northern parts (Movius, 1944 and Movius, 1948). According to the “Movius Line”, some parts of Turkey were located to the south of this line while some parts were located to the north. However, the whole of Turkey should be taken as being south of the “Movius Line” according to existing data that shows rich Acheulean discoveries in Kars and the Caucasus. Thus, the aforesaid line has no validity in terms of Turkey.

Surveys carried out in Turkey up to now, along with existing data, show that Turkey, especially the Anatolia region, played a crucial role in terms of Acheulean culture. Acheulean bifaces are found in all Turkish regions but not so far in the Thrace part of the Marmara region. Does Turkey represent a bridge for the distribution of Acheulean culture into Eurasia? We can answer in the affirmative to this question. However, the transition from Turkey to Europe is still unclear. According to the Acheulean bifaces found densely in southeastern and eastern Regions of Anatolia in Turkey, the most important migration route via Near East Levant Corridor reaching Caucasus has been established on the Anatolia Bridge. In conclusion, Paleolithic caves or open-air sites should be excavated on a line from Hatay to Caucasus – especially in Kars, Ardahan and Iğdır provinces and/or north of the Van province – in order to find Acheulean cultural remains. It will be a great contribution in terms of gathering much more concrete information about the transition of Acheulean culture into the Caucasus.