. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . evidence favours, therefore, amid-Santonian age for the Canico Member at Sao Nicolau. This determination, togetherwith the early Coniacian age assigned to the uppermost observed levels of the SalinasFormation, serves to date Ombe volcanism as Middle Coniacian to Lower Santonian. A mid-Santonian age for the marine transgression responsible for Baba sedimentationis of some significance, since it is of identical age to the major late Cretaceous trans-gressive event along the east coast of Africa (Cooper 1974, 1976), an
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum . evidence favours, therefore, amid-Santonian age for the Canico Member at Sao Nicolau. This determination, togetherwith the early Coniacian age assigned to the uppermost observed levels of the SalinasFormation, serves to date Ombe volcanism as Middle Coniacian to Lower Santonian. A mid-Santonian age for the marine transgression responsible for Baba sedimentationis of some significance, since it is of identical age to the major late Cretaceous trans-gressive event along the east coast of Africa (Cooper 1974, 1976), and accounts for thesimilarity between the Baba and Mzamba molluscan faunas (Rennie 1945; Carvalho1961). The overlying Bero Conglomerate, a proximal shoreline facies, indicates shoalingupward and deposition of the upper Baba Formation under regressive conditions;unfortunately, the latter phase is not yet dated precisely. However, the transgressive-regressive cycle responsible for deposition of the Baba Formation is believed to correlate 152 ANNALS OF THE SOUTH AFRICAN MUSEUM. Figure 3 undata (Conrad), x 1. Interior, lateral, dorsal and anterior views of a left valve,3. E-F. Oscillopha cf. dichotoma (Bayle). x 1. Internal and external views of a rightvalve, SAM-PCA1989. STRA TIGRAPHYAND PALAEONTOLOG Y OF BAB A FORMA TION, SAO NICOLA U, ANGOLA J 53 with Sequence 32 of the global sea-level curve (Haq et al. 1987). All the material described here is housed in the South African Museum, Cape for measurements are as follows: D = shell diameter, H = whorl height,W = whorl width, U = umbilical diameter, c. = circa, applies to measurements which havebeen estimated, whether due to erosion, damage or distortion; all measurements arefollowed, in parentheses, by the dimension as a ratio of the shell diameter. SYSTEMATIC PALAEONTOLOGY Subclass AMMONOIDEA Zittel, 1884 Order AMMONITIDA Agassiz, 1847 Suborder TURRILITINA Besnosov & Mikhailova, 1983 Superfamily BACULITACEAE Gill,
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