The paper deals with the investigation results of the Beganchik site (island) conducted by the authors on the left bank of the Kuybyshev reservoir, the mouth of the Aktai river (Republic of Tatarstan). The stages of the site study are presented. Functional and morphological analysis of the obtained stone artifacts (439 items) of the Ust-Kamskaya culture has been carried out. It was succeeded to find out the bone of a fossil horse lying in situ and to establish its separate stratigraphic position in relation to a cultural layer. The species definition of the bones of large mammals collected on the shallows of the island (80 specimens) showed their belonging to the Mammoth fauna of the Pleistocene (mammoth, woolly rhinoceros, musk ox, horse, bison, etc.). The authors conclude that this paleo-faunal location probably was not connected to the everyday activities of the Final Palaeolithic inhabitants of the Ust-Kamskaya site-workshop.