3«0 



MK.NAKI) AM) LADI) 



[chap. 15 



limestones nearly a mile in thickness. Upward growth appears to have been 

 more important than lateral growth. Many atolls were developed on triuicated 

 volcanoes (giiyots, see Fig. 9) and began their existence as atolls without 



Geology 



Seo level 



11° 17 N 165° 25 E 



Bikini Atoll 



11° 56' N 165° 25' E 



Seo level 



ir46'N 161°58'E 



Eniwetok Atoll 



11° 01 'N 162° 32' E 



Seo level 



Sea level 



I 1000 



£ \ No verticol enaggerorion 



o 2000 1 (^Q slooe correction 



"1 

 10 Statute miles 





ir 50' N 162 55' E Guyot Northeost of Eniwetoh Atoll 11° 39'N 163 08' E 

 Sea level 



'Zv7?V,>\W 



10° 22' N 166° y'E Guyot South of Ailinginoe Atoll 



Sea level 



/////////';/y//y////////A//y/////A 



10° 53' N 166° 32' E 



2' OiN 165° 06' E 



11°42'N 166° 36' E 



Guyot Nortti of Rongelop Atoll 



ir 48' N 166° 10 £ 



Fig. 9. Cross-sections of atolls and guyots ; the peripheries of the guyots are rounded, 

 those of the atolls comparatively sharj). (After Emery vt al., U.S. (Jeological Survey, 

 1954.) 



passing through fringing reef and barrier reef stages. There is convincing 

 evidence to indicate that their history has not been one of uniform and long- 

 continued subsidence. Periodically the Pacific Basin atolls stood above the sea 

 for appreciable intervals, some of them as high islands. During these emergent 



