Article: Buchiid bivalves from the Upper Jurassic and Lower Cretaceous of East Greenland
Bivalves of the genera Praebuchia and Buchia described here occur in great abundance in the Oxfordian to Valanginian Stages of East Greenland. Fifteen species have been identified. Their stratigraphic range is roughly the same as in other Arctic areas, and a detailed zonation based on buchiid bivalves seems to be valid from Arctic Canada over East Greenland to Andoy, Svalbard, Petshora River basin, Subarctic Urals, and northern Siberia. The following zones and beds have been recognized in East Greenland: The Upper Oxfordian Praebuchia kirghisensis Zone, the Kimmeridgian Buchia concentrica and B. tenuistriata Zones, the Middle Volgian B. mosquensis Zone and B. russiensis beds, the Upper Volgian B. fischeriana beds, the Upper Volgian-lowermost Ryazanian B. unschensis-B. terebratuloides beds, the Lower Ryazanian B. okensis Zone, the Upper Ryazanian B. volgensis Zone, the uppermost Ryazanian-lower Lower Valanginian B. inflata Zone, the upper Lower Valanginian B. keyserlingi Zone, the Upper Valanginian-(?) Hauterivian B. sublaevis and B. crassicollis Zones.