View source for BGS Zone 1 (=UKB1 and 2 of Hart et al., 1989)

'''Base:''' The inception of ''Plectina mariae'' and ''Hagenowina anglica''. ''Flourensina intermedia'' and ''Hagenowina advena'' become common. The extinction of the Albian taxa such as ''Arenobulimina chapmani'' and ''Arenobulimina sabulosa''.

'''Top: '''The inception of the succeeding zonal index

'''Biomarkers: '''

* ''Vialovella praefrankei'' becomes extinct in the lower part of the ''N''. ''carcitanense'' macrofaunal subzone.

* Facies related taxa such as ''Bulbophragmium aequale folkestonensis'', which is found in the Glauconitic Marl of southeastern Kent, were used by Hart ''et al'' (1989) to define his UKB 1 Zone.

'''Macrofaunal correlation''': ''M. mantelli'' Zone

'''Age: '''Early Cenomanian

[[Category:Foraminiferal zonation | 001]]