. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. OSTRACODA FROM QUATERNARY COASTAL SEQUENCES 105 gypsiferous beds at the top. We have indicated these changes in Figure 17, but can only speculate that they were contemporaneous with the same part of the cycle at Draaihoek. Ostracod abundances (Fig. 20) are generally lower than found at Draaihoek (< 50 valves/10 g), with the notable exception of the fresh- water sands immediately below the gypsiferous beds (500 valves/10 g), where there is a marked influx in numbers of Sarscypridopsis reniformis (p
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. OSTRACODA FROM QUATERNARY COASTAL SEQUENCES 105 gypsiferous beds at the top. We have indicated these changes in Figure 17, but can only speculate that they were contemporaneous with the same part of the cycle at Draaihoek. Ostracod abundances (Fig. 20) are generally lower than found at Draaihoek (< 50 valves/10 g), with the notable exception of the fresh- water sands immediately below the gypsiferous beds (500 valves/10 g), where there is a marked influx in numbers of Sarscypridopsis reniformis (plus abun- dant Cyprideis remanei and C. draaihoekensis). DRAAIHOEK 60O. Fig. 18. Abundance of ostracods (expressed as number of valves per 10 g of > 250 yi residue) per sediment sample at Draaihoek. In detail there are significant differences between the successions at Draai- hoek and the Gypsum Quarry. Firstly, the normal salinity marine faunas are not the same. At the beginning of the first cycle at Draaihoek, these are dominated by FA 4 (Cytheromorpha milleri), whereas at the Gypsum Quarry they are dominated by the more diver- sified FA 3 {Xestoleberis capensis, Aurila kliei, A. dayii), which we suspect may represent a less open-water, more coastal assemblage. Secondly, Paracypris westfordensis comprises a larger component of FA 1 at Draaihoek, compared to that at the Gypsum Quarry, suggesting that at the former site there was a more persistent inflow of brackish water (which intro- duced allochthonous valves of this taxon) into the high-salinity marine lagoon with its autochthonous Cyprideis remanei and C. draaihoekensis assemblage. Finally, although the freshwater component of the ostracod assemblages throughout the succession at the Gypsum Quarry is almost exclusively Sars- cypridopsis reniformis (FA 5), and Heterocypris capensis does not occur at this. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readab
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
