54 Fred B Phleger 



The present cores contain " upper " and " lower " faunas which are comparable 

 in species composition to those previously reported, with the following exceptions: 

 in the upper, modern assemblage Globigerinoides sacculifera generally is more abund- 

 ant especially in the area farthest off shore, Globorotalia truncatulinoides may be less 

 abundant, and Globigehna eggeri may be more abundant; in the lower fauna, G. 

 inflata and G. pachyderma are less common, being recorded in very low frequencies 

 from only occasional samples. 



The " upper " planktonic core fauna contains the modern assemblage and is 

 assumed to represent conditions similar to those obtaining today, and may be con- 

 sidered to represent relatively warm surface water. The " lower " fauna contains 

 fewer North Atlantic low-latitude planktonic specimens and consequently more 

 mid-latitude forms, and is considered to represent a time of cooler surface water. 

 Interpretation of these distributions may be clarified by examination of the data and 

 discussion in Phleger et al. (1953) on distributions of North Atlantic planktonic 

 Foraminifera. 



Lower, colder-water faunas were present in eight of the fifteen cores examined. 

 The interpretations of the faunas are summarized in Fig. 3, and the faunas on which 

 these interpretations are based are listed in Tables II-IV. Cores 3, 4 and 6 contain 

 two cold-water faunas separated by a warm-water fauna and their lower sections 

 contain an additional warm-water fauna. Cores 5, 7, 8, 11 and 14 contain a cold- 

 water fauna in their lowermost sections. The other cores contain the modern Gulf of 

 Mexico planktonic fauna throughout their entire lengths. Core 18, on the lower 

 continental shelf at a depth of 88 m, contains few planktonic specimens. 



The benthonic Foraminifera in most of the core samples are normal for the water 

 depths at which the cores were collected (see Phleger, 1951, Figs. 22-25; Parker, 

 1954, Figs. 3-9). Striking exceptions occur in cores 9 and 10. In core 9, from 1372 m 

 depth, the bottom sample at 158-163 cm contains the following shallow-water 

 (continental shelf) species in significant frequencies: 



Angulogerina be I la Phleger and Parker 



Bolivina barbata Phleger and Parker 



B. striatula spinata Cushman 



Bulimina marginata d'Orbigny 



Buliminella cf. bassendorfensis Cushman and Parker 



Elphidium spp. 



Globobulimina mississippiensis F. L. Parker 



Nonionella opima Cushman 



Rectobolivina advena (Cushman) 



" Rotalia " beccarii (Linne) variants 



Virgulina pontoni Cushman 



A few of these species occur in lower frequencies from 145-158 cm, and single 

 specimens of Bolivina striatula spinata, Buliminella cf. bassendorfensis and Liebusella 

 sp. occur at 3-8 cm in the core. Most of the benthonic Foraminifera in this core are 

 normal for the depth at which the core was collected. Quartz grains of fine sand size 

 and wood fibres which are coloured dark brown occur from 85 cm to the bottom of the 

 core. 



