Cross-bedding and facies of the Obolus beds of the Baltic region

Under the category of Obolus beds, we understand the portion of the Cambrian-Ordovician section, corresponding in the scheme of the Interdepartmental Stratigraphic Committee (1962), to the lower, sandy half of the Pakerort horizon, assigned to the Tremadocian stage of the Lower Ordovician (4, 11, 12, 22, etc.). Most investigators regard the Obolus beds as formations of the nearshore zone of a vast bay (10, 12, 14, 16, 24) or quite a narrow strait (4).