Base of the Upper Devonian in the Conodont Zonation
Johnson, J. G.
published: Jan 1, 1988
ArtNo. ESP026002101010, Price: 29.00 €
The base of the Lower asymmetrica Zone has been displaced backward in time as the early evolution of its definer, Ancyrodella rotundiloba, has been made known. Assertions that the base of the zone can remain stable, without redefinition, lack a viable basis such as location in a stratotype.