-f>' 



IV DEPTHS AND DEPOSITS OF THE OCEAN 165 



being apparently remov^ed through the solvent action of sea- 

 water, and with in- 

 creasing depth the 

 Globigerina ooze 

 passes gradually into 

 another pelagic type, 

 usually Red clay. 



Diatom Ooze. We Diatom ooze. 



have indicated that in 

 the colder regions of 

 the ocean, as in the 

 great circumpolar 

 Southern Ocean and 

 along the northern 

 border of the Pacific, 

 diatoms flourish abun- 

 dantly in the surface 

 waters, and where de- 

 trital matters are not 

 very large in amount 

 their dead frustules, 

 falling to the bottom, 

 make up a large part 

 of the deposit called 

 ^^>t. I& Diatom ooze (see Fig. 



■/// Radio larian Ooze Radioiaiian 



;/ (see Fig. 141) has not °°^^- 



been recorded from the 

 Atlantic Ocean, but is 

 characteristic of deep 

 water in the tropical 

 regions of the Pacific 

 and Indian Oceans, 

 , where the surface 



\:,^' waters have rather a 



low salinity and carry 

 clayey matter in sus- 

 pension. It may be 

 Fig. 141.-RA1.10LARIAN Ooze. regarded as a variety 



Valdivia" Station 237, Indian Ocean, lat. 4° 45' S. , P-r^ A \ «- ' ' 



long. 48° 58'. 6 E., 2772 fadioms (magnified). OI KeQ Clay COntammg 



Fig. 140. — Diatom Ooze. 

 Valdivia" Station 140, Southern Ocean, lat. 54° 

 long. 22° 13'. 2 E., 2207 fathoms (magnified). 



' It may be noted that Flint has recorded Diatom ooze from the tropical Pacific, but his 

 samples have since been examined and classed by us as Radiolarian ooze. 



