on board H.M.S. 'Challenger.* 523 



soai3 of the shallower soundings only a trace of clayey matter remained 

 with a perceptible rose tinge. No casts of the Forarninifera were noticed 

 about Bermuda. 



At the Virgin Islands, at Tongatabu, at Eiji Islands, at Cape York, 

 Admiralty Islands, Honolulu, and Tahiti we also met with coral-muds. 

 Except at Cape York, these muds appeared to exist as a narrow band 

 around the land, and had usually a considerable admixture of clayey 

 matter and mineral particles. 



"Where there was much clayey matter we found usually a few rough 

 red casts of the Eoraminifera. 



The following is a list of the depths of the soundings included under 

 coral-muds : — 



At Bermuda. At other places. 



fms. 



fms. 



fms. 



2250 



2100 



1250 



1820 



1950 



1575 



950 



2650 



1500 



430 



1325 



200 



1375 



1075 



37 



2450 







fms. 



fms. 



fms. 



4601 



1401 



210/ 



25 



390 L 



100 



625 J 



6101 



40 



18] 



70 I 



90 



240 



25 J 



100 



315 f 



16 





255 J 







2. Globigerina-ooze. — After the deep-sea clays, this is the most abun- 

 dant deep-sea deposit. It has occurred at all depths from 250 fathoms 

 to 2900 fathoms. The Globigerince, which give at once the name and 

 the chief characteristic to this deposit, are really found all over the bot- 

 tom of the ocean. Even in our deepest clays, if the surface-layers be 

 selected and all the amorphous matter be washed away, one or two shells 

 of some variety of pelagic Eoraminifera can usually be detected. By 

 pursuing this method I have only failed on one or two occasions. They 

 appear to be quite absent in the Arafura Sea. It is, however, when they 

 occur in vast numbers that they form the deposit known by this name ; 

 at least such is the sense in which it is here used. 



We did not find a Globigerina-ooze in any of the enclosed seas, in the 

 Southern Ocean south of lat. 50° S., nor in the North Pacific north of 

 lat. 10° N. 



In the Southern Ocean only one small species of Globigerina was found 

 in the surface-waters ; but in the North Pacific many varieties of pelagic 

 Eoraminifera abound near the surface of the ocean. 



In other parts of the preceding oceans, and in the other oceans we 

 have visite'd, it occurs in irregular patches, being always present in the 

 open ocean when we have depths of less than 1800 fathoms. Its pre- 

 sence or absence at depths beyond 1800 fathoms is, however, determined 

 by conditions at present unknown. A number of varieties occur both as 

 to colour and composition. Some specimens are nearly pure white, 

 others have a rose-colour, and others are red or dark brown. The red 

 and brown colour arises from the presence of the oxides of iron and 



