The lowermost section from 214.1’-306’ (65.3-93.3m) belongs to East Coast Diatom
Zone 1 (ECDZ 1). It represents a thick sequence of middle Burdigalian (lower Miocene) strata
that corresponds to the calcareous nannofossil zone NN2 of Martini (1971) and dinoflagellate
zones DN2a-DN3 of de Verteuil and Norris (1996) (as delineated in Alemán et al., in press).
Important diatom marker species identified in this section include Actinoptychus heliopelta,
Biddulphia minuta, Raphoneis fossile, Sceptroneis caduceus, and Raphoneis. margaritata. The
top of this zone is marked by a lithologic contact described in Alemán et al. (in press) that is
interpreted as the hiatus described by Andrews in his A. heliopelta Assemblage Zone (Andrews,
1977).