OCEAN BOTTOM— PIGGOT 215 



If the apparatus has fired, the gun is hoisted up until the bit can 

 be gotten over the side ; this is laid in its proper chocks, and the gun 

 then lowered to its chocks. 



Sixteen soundings were made at sea in August 1935, yielding the 

 14 cores shown in plate 3, figure 1. One failure was due to a defec- 

 tive primer, and once the core pulled out. The 14 cores vary in 

 length from 4 feet to nearly 9 feet and are solid throughout. The 

 depths of these soundings varied from 200 fathoms to 1,250 fathoms. 



The 11 cores shown in plate 3, figure 2, were obtained during May 

 1936, between the Grand Banks of Newfoundland and the edge 

 of the continental shelf west of Ireland. Seven of them are from 

 depths greater than 2,000 fathoms and all the remainder but one 

 from more than 1,000 fathoms. The one exception is from the top 

 of the Faraday Hills at 700 fathoms. The greatest depth was 2,650 

 fathoms. The very short core contains several inches of rock. 



Plate 4 shows these cores split open ready for study, arranged, 

 as taken, from west to east across the North Atlantic, and plate 5 

 a more detailed view of some of them showing the stratification 

 and change of character of the material. 



The cracks are due to drying. This can be prevented by keeping 

 the cores in a saturated atmosphere, but since the dried segments 

 leave marks on the brass troughs which establish their positions 

 from the surface this is not usually done. 



DISCUSSION 



These samples are of interest to many investigators. The marine 

 biologists and micropaleontologists will find in them the remains 

 of marine organisms which lived ages ago in the waters above. 

 These organisms will change in character, from level to level of the 

 core, reflecting their evolutionary development and the changes of 

 type brought about by changes in the temperature of the water. 

 Thus it may be possible to state that throughout a certain period 

 in the past the water was much colder, or warmer, in that portion 

 of the ocean. Or the}'' may show that it was shallower — a mere 

 lagoon, or deeper. The sedimentologist by a study of the minerals 

 and the size of the particles of rock will be able to trace the changes 

 of direction and possible force of ocean currents throughout past 

 ages. The character of the sand and pebbles will indicate the pres- 

 ence of ice or the proximity of land where only ocean exists today. 

 No one of these bits of evidence will be conclusive in itself, but many 

 taken together may build up a strong corroborative presumption of 

 a certain condition. 



Some chemical and mineral constituents are of great significance, 

 as for mstance the fluorine and clilorine and other acid or basic radi- 



