There is suggested the hypothesis of the lower world spirits appearance at the petroglyphs of Amur. With this purpose, there are considered the pictures on two stones of Sikachi-Alyan. The author uses own method of the systemic description of the masks to reveal the common features in the image structure and in the artistic image. Their combination lets compare the visual image of the stone picture with the signs of mythological personages of the Amur Paleoasians and the Tungus.