Raw materials and stone tool manufacture and use patterns on the Ilskaya Mousterian site (Northwestern Caucasus)
The materials of Ilskaya are of outstanding importance for the study of the Middle Paleolithic period in the south of Russia. The lower cultural layers of the site (layers 5–7 of its eastern section) occur in alluvial deposits of the third terrace, which can be synchronized with the last (Eem or Mikulino) interglacial and dated to OIS 5e. The upper cultural layers (layers 1–4 of the eastern section) are associated with deluvial deposits of the same terrace and formed in the beginning of Wurm (Valdai). Cultural layers 3 and 4 can be provisionally correlated with OIS 5b–5d, whereas cultural layer 2 appears to be coeval with the Odderade interstadial (OIS 5a). The uppermost cultural layer 1 is dated to the first cold maximum of the Valdai glaciation (OIS 4) or early OIS 3. The industry of the site can be defined as Mousterian or Levallois-Mousterian with a small component of bifacial tools (Ilskaya type industry). Primary flaking was based on the Levallois technology. To produce their stone artifacts the inhabitants of the site used dolomite, various kinds of flint, as well as lydite and silicified varieties of aleurolite and sandstone. The unequal quality of raw materials conditioned the differences in their use. The main categories of tools, represented by various points, side-scrapers, and backed bifacial knives (Keilmesser) are made of flint and silicified rocks. They had long lives. Due to periodical rejuvenation they decreased in size, while their forms remained almost unchanged. By contrast, the artifacts of dolomite (mainly flakes and intermittently retouched blades) were not resharpened after use, bur merely discarded and replaced with new ones. Best of all this is reflected in the materials of cultural layer 3, which were studied completely. In technological and typological respects the stone inventory of this layer differs from those of the other cultural layers of Ilskaya, though there are some common traits, too. The available evidence shows that the inhabitants of the site had to adjust their technologies to the peculiarities of the raw materials they used.