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ANNUAL REPORT SMITHSONIAN INSTITUTION, 1947 



Society investigation of Funafuti (1904). In that case a magnetic 

 survey was made before the boring was attempted. The results showed 

 a magnetic high close to the western margin, on the lee side. It was, 

 therefore, deemed desirable to drill on the western margin, but un- 

 fortunately it was not possible to get the equipment on this location 

 so the boring was made on the eastern rim instead. (See figs. 14 and 

 15.) 



In 1944 the writer found a guyot centered about 20 miles northwest 

 of Bikini and made four NE.-SW. profiles across it. During the 

 Crossroads Operation the Navy surveyed this guyot, making a number 



SEALEVEL 



eoola 



ISOSTATIC \SETTLING AS 

 A RESULfVOF LOAD 



FiouEE 14. — Relations between the top of a late Pre-Cambrian guyot and the vol- 

 canic core of an old Paleozoic atoll. Settling because of loading by limestone 

 has depressed volcanic core of the atoll below the level of upper flat surface of 

 guyot. 



of NW.-SE. sounding traverses over it, so that its outline and form 

 are now well known. It has a flat upper surface at 700 fathoms (4,200 

 feet) and is separated from the northwestern slope of Bikini by a low 

 saddle. 



If the writer's hypothesis were correct, that the surface of the guyot 

 became submerged in pre-Cambrian time before the appearance of reef - 

 building organisms, how could nearby Bikini Atoll have grown up 

 from a peak which is now deeper, i. e., 5,500 feet below sea level? 

 This peak would be more than a thousand feet below the top surface of 

 the guyot. It might be supposed that the peak under Bikini comes 

 much closer to the surface west of the investigated area, and therefore 

 might have been both younger and higher than the adjacent guyot 

 surface. Thus it would have been able to support reef-building 

 organisms after the guyot was planed off. However, let us disregard 

 this possibility for the moment and consider the more fundamental 



