1183 ISSN 1028-334X, Doklady Earth Sciences, 2007, Vol. 417, No. 8, pp. 1183–1187. © Pleiades Publishing, Ltd., 2007. Original Russian Text © D.V. Grazhdankin, K.E. Nagovitsin, A.V. Maslov, 2007, published in Doklady Akademii Nauk, 2007, Vol. 417, No. 1, pp. 73–78. Upper Vendian rocks of the East European Platform (EEP) are characterized by the presence of the White Sea fossil biota, which colonized the region from the southeastern White Sea area to the Central Urals [1]. The White Sea biota includes ecological assemblages of the Avalon (Newfoundland), Ediacara (South Aus- tralia), and Nama (Namibia) types, each related to cer- tain environmental conditions [2]. In 2006, we found a previously unknown and morphologically diverse assemblage of carbonaceous macroscopic fossils in the fine-grained aluminosiliciclastic rocks of the Perevalok Formation (Sylvitsa Group) in the Central Urals. Together with the organic-walled macrofossils from the rocks of the Lyamtsa Formation (Valdai Group) in the southeastern White Sea area, the carbonaceous fossils from the Perevalok Formation represent a new (fourth) ecological assemblage of the White Sea fossil biota. The ecological assemblage is older than 557–558 Ma [3, 4] and includes macroscopic microbial colonies, multicellular and coenocytic eukaryotic macroalgae. In the Late Vendian history of the EEP, this assemblage predated the appearance of the world’s most diverse soft-bodied assemblage, which was found in the over- lying rocks of the White Sea area (Verkhovka and Erga formations) and Central Urals (Chernokamen Forma- tion) [1, 2, 5]. The carbonaceous fossils are confined to a thick (200–400 m) transgressive sequence at the base of the Upper Vendian succession in the southeastern White Sea area and Central Urals (Fig. 1). The lower part of the sequence (laminated mudstones with layers of vol- canic tuffs) is gradually replaced upsection by thinly interbedded siltstones and mudstones with rare layers of wave-bedded sandstones. The sequence was formed by the advance and periodic retreat of storm-dominated coastal depositional setting into subaqueous muddy planes with relatively quiet sedimentation in the course of oscillating wane in transgression. Fossiliferous inter- vals contain thin laminae of phosphorites and organic matter and mark the peak of shallow-water transgres- sion over the platform. In the southeastern White Sea area, this sequence correlates with the Lyamtsa Forma- tion and lower part of the Verkhovka Formation; in the Central Urals, with the upper part of the Staropechny and Perevalok formations [6, 7] (Fig. 1). In the southeastern White Sea area, a diverse assem- blage of organic-walled macrofossils of the Lyamtsa Formation was found in the core from borehole C18 (depth 214–54 m), which was drilled in 1996 on the right bank of the Agma River Valley, Onega Peninsula [3]. The assemblage is dominated by compressed spherical chuariamorph fossils of Beltanelloides sorichevae Sokolov, but special attention should be given to the fragments of geniculated compressed hol- low tubes (up to 80 mm long and 9 mm wide) of Sino- spongia chenjunyuani Chen with thin regular trans- verse wrinkles (Figs. 2d, 2f). In view of the small core size, the tube ends were not observed. In some places, collapsed organic matter is preserved along the tube axis as a dark brown carbonaceous ribbon with impres- sions of transverse wrinkles (Fig. 2e). The organic mat- ter of the tubes is thin, yellow, and structureless. In addi- tion to Sinospongia, the Lyamtsa Formation contains rel- atively narrow (1–1.35 mm wide) curved compressed tubes of Jiuqunaoella simplicis Chen (Fig. 2g) with thin light yellow walls and thin transverse wrinkles. Their content is collapsed into chains of brown ovoid spots of organic matter with fold impressions (Fig. 2h). The Lyamtsa assemblage also includes narrow (0.85–1 mm) relatively thick-walled dark brown sinusoid com- pressed tubes with thin transverse wrinkles (Fig. 2i). In addition to tubular fossils, optically dense wide (up to 6 mm) ribbon of Mezenia kossovoyi Sokolov was found in the mudstones of the Lyamtsa Formation. Its smooth surface was distorted during burial by weak transverse undulation, sharp longitudinal and arched Late Vendian Miaohe-type Ecological Assemblage of the East European Platform D. V. Grazhdankin a , K. E. Nagovitsin a , and Corresponding Member of the RAS A. V. Maslov b Received May 15, 2007 DOI: 10.1134/S1028334X07080107 a Institute of Petroleum Geology and Geophysics, Siberian Branch, Russian Academy of Sciences, pr. Koptyuga 3, Novosibirsk, 630090 Russia; e-mail: f6oeoua@mac.com b Zavaritskii Institute of Geology and Geochemistry, Ural Division, Russian Academy of Sciences, Pochtovyi per. 7, Yekaterinburg, 620219 Russia GEOLOGY