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Calcareous algae are common components in the shallow-marine limestones of the Drunka Formation (Early Eocene) cropping out on both banks of Nile between Sohag and Quena. Calcareous algae include: Acicularia valeti Segonzac, Sandalia pavsici Radoicic, Clypeina occidentalis (Johnson and Kaska), C. cf. rotella Jing, Terquemella bellovacensis Munier-Chalmas (Dasycladales), Ovulites arabica (Pfender), O. pyriformis Schwager, O. margaritula (Lamarck), O. elongata Lamarck (Udoteaceae), Halimeda tuna (Ellis and Solander) Lamouroux, H. opuntia (Linneaus) Lamouroux and H. fragilis Taylor (Halimedaceae). Niloporella subglobosa n.gen.n.sp. and Acicularia robusta n.sp. are new calcareous algae. Among fossil Halimeda three evolutionary lineages are recognized in the the Mesozoic and early Cenozoic that derive from Paleozoic Protohalimedaceae: Halimeda cylindracea lineage, H. incrassata, and H. opuntia.
First and last occurrences of several Maastrichtian calcareous nannofossil species are shown to be diachronous across paleodepth and paleoenvironment using the graphic correlation method. Calcareous nannofossil assemblages examined from eleven cores from a deep- to shallow-water transect along the eastern United States Atlantic margin document that the first occurrence of Micula murus (Martini 1961) Bukry 1973 is diachronous, appearing 2.0 million years earlier in open ocean sites than in shallow marine sites. The first occurrence (FO) of Lithraphidites kennethii Perch-Nielsen 1984 is also nonsynchronous, appearing in the deep ocean before its FO in neritic waters. The last occurrence (LO) of L. praequadratusRoth 1978 is diachronous across paleodepth, going locally extinct first in deeper water. The LO of Watznaueria bybelliaeSelf-Trail 1999 is also diachronous, going locally extinct first in shallow-water settings. Ceratolithoides amplector Burnett 1997, C. pricei Burnett 1997, C. self-trailiae Burnett 1997, C. ultimus Burnett 1997, Cribrocorona gallica (Stradner 1963) Perch-Nielsen 1973, Micula praemurus (Bukry 1973) Stradner and Steinmetz 1984, Pseudomicula quadratusPerch-Nielsen et al. 1978, and Semihololithus spp. are present consistently in common to frequent abundances in ODP holes 1050C and 1052E on the Blake Nose, but they are rare or absent from neritic sections in Coastal Plain cores. It is apparent that these species flourished in an open ocean setting, suggesting that differences in assemblage abundance and diversity between deep ocean and nearshore areas were controlled by paleoceanographic factors. These species are not used for biostratigraphy, but may be useful indicators of open ocean conditions. The line of correlation (LOC) for nine Coastal Plain cores clearly defines the Cretaceous-Tertiary (K/T) boundary unconformity at the top of the Maastrichtian section (Peedee Formation) and the Campanian-Maastrichtian (C/M) unconformity at the base of the Maastrichtian section (Peedee/Donoho Creek formational contact). The K/T boundary unconformity is undulatory in nature; updip Maastrichtian sections have been stripped to a greater depth than the downdip sections. The uppermost Campanian, all of the lowermost Maastrichtian, and the basal upper Maastrichtian sediments are missing from the study area.
The comparison of superposed praealveolinid assemblages from the well exposed outcrops in the Iberian Range and the Pyrenees with Prealveolina species from the type localities in Reichel's collection have allowed us to evaluate the stratigraphical range of each species.
The species Praealveolina iberica, P. pennensis and P. debilis successively replace each other from Early to Mid Cenomanian; they have been correlated with Mantelliceras mantelli and Acanthoceras rotomagense ammonite zones, and with Rotalipora brotzeni and the lower part of the R. cushmanni planktonic foraminiferal zones. Praealveolina brevis and P. tenuis appear successively during the Upper Cenomanian, but the range of P. tenuis may overlap with the one of P. brevis in the Early Upper Cenomanian; they have been correlated with Calycoceras naviculare and Metoicoceras geslinianum and with R. cushmannni zone. P simplex occurs together with P. brevis and P. tenuis in the Upper Cenomanian. The stratigraphic relationship of P. cretacea and P. lata with the species treated in this paper have not been established yet because they were not found in the studied sediments.
Both Azpeitia endoi and Azpeitia tabularis, which are referred to the Azpeitia tabularis group, are described based on light microscope and SEM observations. Samples came from living material collected on the KH99-3 cruise in the Bering Sea, from fossil Pliocene and Pleistocene material in DSDP Holes 579A and 580 in the northwest Pacific Ocean, and from the Middle Miocene of the Oga Peninsula, northeast Japan. Both these species occurred in the Middle Miocene, and A. endoi has the central depression which is common feature in the genus Azpeitia, while A. tabularis does not. Since A. tabularis does not posses the central depression, A. endoi is considered to represent the ancestral condition for A. tabularis.
One new foraminiferal genus Sirelella (type species Sirelella safranboluensis) is described and figured from the Lutetian shallow-water limestones of Safranbolu area, Southeast of Bartın (Northern Turkey). It is characterized by the presence of the trochospiral early orbitoidal adult chambers and by the lack of vertical canals in the large umbilical plug.
Drying of marine sediment samples is required to determine the number of foraminifers per g as an indication for paleoenvironmental changes. Our results show that oven-drying may lead to alteration of the stable oxygen isotope signal. The δ18O values of Turborotalita quinqueloba (Natland) from dried samples are as much as 2.8‰ lighter than their equivalent from samples which were not dried before preparing. Differences in the isotopic composition of Bulimina aculeata (d'Orbigny) were less dramatic (<0.5‰). The drying as well altered the composition of benthic assemblages, thus oven-drying should be generally avoided.
A new species of Laffitteina (foraminifera) is described from the Maasrichtian of the Tecer (Central Anatolia -Sivas). It is named as Laffitteina turcica n.sp. It differs from the other Laffitteina species by its low lenticular test shape and overall dimensions.