Onega Bay Onega Bay The Onega Bay () is located in the Republic of Karelia and Arkhangelsk Oblast in Northwestern Russia, west of the city of Arkhangelsk. It is the southernmost of four large bays and gulfs of the White Sea, the others being the Dvina Bay, the Mezen Bay, and the Kandalaksha Gulf. The area of the bay is . The Onega Bay is long and - wide. The average depth of the bay is , and the maximum depth is . The bay freezes in winter. Onega, Kem, and Vyg Rivers flow into the bay. The bay has numerous islands.
Onega stepanovi placed in phylum Proarticulata, as the segments in recently discovered, exceptionally well-preserved fossils display the glide, or "staggered", symmetry characteristic of the majority of proarticulatans. Imprints of "Onega stepanovi" have been found in the Verkhovka and Zimnie Gory Formations of the Ediacaran (Vendian) rocks of the Arkhangelsk Region, Russia. All the fossil specimens are negative imprints on the bases of fine-grained sandstone beds with the "elephant skin" and tubercle texture diagnostic of microbial mats. The same bedding planes contain various other Ediacaran species: "Cyclomedusa", "Ediacaria", palaeopascichnids, "Eoporpita", "Yorgia", "Andiva", "Archaeaspinus", "Vendia", "Dickinsonia", "Anfesta", "Albumares", "Tribrachidium", "Kimberella", "Parvancorina", "Charniodiscus" and others.