64 UPPER CRETACEOUS-LOWER TERTIARY FORAMINIFER A 



The zone is characterized by the abundance of the following Globorotalia species : 

 G. angidata angulata, G. angidata abundocamerata, G. ehrenbergi, G. emilei, G. faragi, 

 G. imitata, G. perclara, G. pseudobidloides, G. pusilla pusilla, G. pusilla laevigata, G. 

 pusilla mediterranica, G. quadrata, G. tribulosa, G. uncinata uncinata, G. uncinata 

 carinata and G. sp. It is also distinguished by the abundance of the following 

 Globigerina species : G. haynesi, G. inaequispira, G. kozlowskii, G. spiralis, G. trilo- 

 culinoides and G. triloculinoides parva. 



It is divided into two distinct subzones : a lower, Globorotalia uncinata Subzone 

 and an upper, Globorotalia pusilla Subzone. The ranges of the various species 

 characteristic of each subzone are shown on Text-figs. 12-16. 



The G. angidata Zone coincides with the upper part of the Carysomilia granosa 

 Zone of the macrofossil classification. Its planktonic Foraminifera as well as its 

 stratigraphical position (conformably overlying typical Upper Danian strata and 

 underlying the G. velascoensis Zone of Upper Paleocene age) proves its Middle 

 Paleocene age. However, as discussed earlier, the controversy over the chrono- 

 logical and stratigraphical relationships of the various Paleocene stages and sub- 

 stages, and the disagreement regarding their planktonic foraminiferal content, does 

 not allow one to refer the G. angulata Zone to any known Paleocene stage or substage 

 (see pp. 22-29, 59-61). 



8. The Globorotalia velascoensis Zone. 



This is the sixth planktonic foraminiferal zone from the base of the succession 

 upwards. It coincides with the upper two members of the Owaina formation, the 

 Middle Owaina chalk and the Upper Owaina shale members, and represents the Upper 

 Paleocene of the sections studied. It is characterized by the flood of Globorotalia 

 velascoensis velascoensis (Cushman) and its two subspecies parva and caucasica, 

 which are here considered as the index species for the zone. 



The lower limit of the zone is marked by the first appearance of G. velascoensis 

 velascoensis, and its upper limit by the complete disappearance of the last survivors 

 of this species. The lower limit is also defined by the first appearance of the following 

 Globorotalia species : G. acuta, G. apanthesma, G. cf. convexa, G. occlusa, G. pseudo- 

 menardii, and the first appearance of both Globigerina velascoensis and alanwoodi. 



Its upper limit, besides being defined by the disappearance of G. velascoensis 

 velascoensis, is also marked by the disappearance of the following Globorotalia 

 species: G. acuta, G. angidata angulata, G. apanthesma, G. cf. convexa, G. nicoli, and 

 by the disappearance of the following Globigerina species : G. velascoensis, G. tri- 

 locidinoides, G. triloculinoides parva, G. inaequispira, G. haynesi, G. chascanona, 

 G. bacuana, and by the first appearance of Globorotalia bollii. 



The G. velascoensis Zone is generally characterized by the abundance of the 

 following Globorotalia species : G. velascoensis velascoensis, G. velascoensis parva, 

 G. velascoensis caucasica, G. acuta, G. aequa, G. africana, G. angulata angidata, 



