Сultural deposits of Early Holocene was found at the Ostrov Listvenichniy, which was opened during the work on the Angara River, in the flood zone of Boguchanskaya HPP in 2011–2012 field seasons and the rescue operations. In the process of uncovering the later Mesolithic horizon 5, it was identified three objects, which are traditionally referred to as "klad" (treasure) in the Russian archaeological literature. During the research, authors were faced with the problem of using the term "klad" which used to refer to these closed complexes of artifacts and offered their own, in their opinion, more neutral and universal at the same time, term "deposit" takes into account the specifics of the study of fossil prehistoric past. The deposits of artifacts, located in borders of a cultural layer and structurally interconnected with it on the composition, demonstrate production sets, which are arranged in a certain technological chains, both confirming and supplementing the links of the technological process at the site. Bones artifacts are composed of deposits on the one hand confirm the cultural unity with materials of the Mesolithic horizon 5, on the other hand, significantly enrich the tool composition of the site. In conclusion noted that Ostrov Listvenichniy deposits of artifacts is one of the oldest objects on the territory of the Baikal Siberia today.