Arkhangelsk 1553; two disappeared, and one ended up in the White Sea, eventually coming across the area of Arkhangelsk. Ivan the Terrible found out about this, and brokered a trade agreement with the ship's captain, Richard Chancellor. Trade privileges were granted to English merchants in 1555, leading to the founding of the Company of Merchant Adventurers, which began sending ships annually into the estuary of the Northern Dvina. Dutch merchants also started bringing their ships into the White Sea from the 1560s. Scottish and English merchants also traded in the 16th century; however, by the 17th century it was mainly the
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.