Article: Cretaceous and Tertiary coccoliths from Atlantic seamounts
Fragments of white chalky limestone dredged from Galicia Bank off the west coast of Spain contain coccoliths of two different ages. At a station on the northern slope, all the fragments have coccoliths of Middle Eocene age; the same species are also present on Muir Seamount, north-east of Bermuda, but are unknown in any rock exposed on land. In a sample from the underwater escarpment on the east side of Galicia Bank, only Cretaceous species can be recognized. Material dredged from the top of the bank has an intimate mixture of well-preserved Maestrichtian and Middle Eocene species in the same rock. This composite assemblage is believed to have been brought together by mud-feeding organisms which burrowed through a thin layer of Eocene sediment into an unconsolidated Cretaceous ooze below. Three new genera, Colvillea, Ericsonia, and Favocentrum, and eleven new species, are described.