THE FLOOR OF THE OCEAN BOSWELL 281 



we are obliged to consider the possibility of the cable having sunk 

 in the ooze. 



For many years before the Challenger expedition the pioneer 

 methods of bottom-sampling by means of lead sinkers were fol- 

 lowed, but subsequent improvements in technique led to the recovery 

 of samples in valved tubes, that is, small borehole samples were 

 obtained. Even then, only the surface layer of the sea bottom 

 was penetrated. Efforts have therefore been directed to obtaining 

 longer and still longer cores from the ocean floor; the Meteor obtained 

 cores 1 meter in length, and the Snellius afterward brought up 

 cores of a length of 2 meters or more. The possibility of obtaining a 

 stratigraphical succession of floor deposits is fascinating to geologists, 

 because clues to changing conditions of fauna, climate, and depth 

 during geological ages may thus be yielded. 



One of our own most versatile investigators, the late Prof. John 

 Joly, of Dublin, devised a form of deep-sea apparatus for obtaining 

 core-samples. More recently, Dr. C. S. Piggot, recognizing the 

 necessity of improving on the results obtained by the ill-fated American 

 research ship Carnegie, has devised a new type of apparatus, by which 

 the contact of the sampler with the sea floor actuates the trigger of a 

 firing mechanism and so forces the tube down farther than the few feet 

 to which it would be driven by the momentum of the falling weight. 

 Experimental work indicates that cores from 4 feet to 8 feet 8 inches in 

 length can be obtained from depths varying from 200 to 1,250 fathoms. 



Already, however, the older method of coring has shown the 

 presence of different deep-sea deposits in superposition; of globi- 

 gerina ooze resting on blue mud, and of red clay overlying globigerina 

 ooze, as noted by Correns in his accounts of the Meteor samples. 

 Now W. Schott's statistical studies of the fauna of South Atlantic 

 waters indicate that at a depth of about 25 cm in the ooze, warm- 

 water foraminifera such as Globorotalia menardii cease to occur, 

 while Globigerina bulloides and G. inflata which favor cooler but 

 still temperate waters increase in quantity. This kind of faunal 

 variation, already conjectured by Philippi, the geologist to the 

 Gauss expedition, suggests that the deep-sea deposits can furnish 

 evidence of a climatic change. That the variation is not due to 

 the drifting currents is shown by the similarity of the present dis- 

 tribution in the Middle and South Atlantic of G. bulloides in oceanic 

 waters and in the superficial floor deposits. It is possible that the 

 underlying deposits from which Globorotalia menardii is absent were 

 laid down during a recent cold period — perhaps the last phase of the 

 Ice Age. Further, if we assume that the area occupied by the limeless 

 red clay is extensive because cold deep waters are strongly solvent on 

 calcareous skeletons, the fact that red clay overlies a globigerina 

 ooze, which in turn overlies beds with warm-water forms, suggests 



