DEEP-SEA DEPOSITS 85 



coming from the surface of the red clay, proving that it 

 is relatively rich in radium. 



Oceanographers of the present are unfortunately not 

 able to make such excursions over the ocean floor. 

 Instead, we have to send into the depths our instruments, 

 trawls, dredges, and coring devices for sampling the 

 sediment carpet and bringing the catch up to the surface 



Fig. 3 1 . Tooth from giant shark 



for examination and analysis in the laboratory. In 

 Chapter 3 I tried to describe how this is achieved and 

 how, thanks to new techniques and instruments, we are 

 now able to measure the thickness of the sediment carpet 

 by seismic methods and extract cores from its upper 

 layers exceeding 60 feet in length, that is, at least six 

 times longer than was possible only ten years ago. 

 What information has been obtained from these 



