XII 



CONTENTS 



CH. fi. TiiK C'rustal Rocks % R. W . Raift 

 1. Introduction .... 



■1. Lay(M' l> 



."^ Layer W . 



4. Average oceanic crust 



CH. 7. The Mantle Rocks hy .1 . J. Ewing . 



1 . Tntroduction .... 



2. Compressional-wavo measurenients 

 13. .Sliear-wave nieasurements . 

 4. Summary ..... 



CH. 8. Exploration of Sub-Oceanic Structure by the Use of 

 Seismic Surface Waves by J. Oliver and J. Dorman . 



1. Introduction ..... 



2. The general nature of seismic surface waves 

 .'}. Evidence from mantle surface waves 



4. Evidence from crustal surface waves 



5. Evidence from short-period surface waves 



CH. 9. Gravity at Sea by J . Lamar Worzel and J. C. Harrison 



1. Introduction ....... 



2. Methods and theory ...... 



3. Gravity observations and geological interpretations 



CH. 10. The Magnetic Field over the Oceans by E. C. BuUard and 

 R. G. Mason ....... 



1. Historical ....... 



2. Measurement of the magnetic field at sea 



3. General features of the field 



4. Reduction of magnetic observations 



5. The magnetic properties of submarine rocks . 

 f). The magnetic surveys of the north-east Pacific 

 7. The continental shelves .... 

 S. Seamounts and mid-ocean ridges . 

 9. The deep trenches ..... 



CH. 11. The Flow ok Heat Thkoi'oh the Floor of the Ocean Jnj 

 E. C. Bullard .... 



1. Method 



2. The temperature probe 



3. The thermal pro|)eities of sediments 



4. The results t)f heat-How measurements 



5. 



Future work 



85 

 85 

 91 

 99 

 101 



103 

 103 

 103 

 105 



107 



110 

 110 



111 



117 

 121 

 126 



134 

 134 

 134 

 154 



175 

 175 



177 

 185 

 190 

 192 

 193 

 203 

 206 

 210 



21 S 

 218 

 218 

 222 

 227 

 231 



Section II. Topography and Structure 



233 



CH. 12. Topography of the Deep-Sea Floor by Bruce C. Heezen and 



H. W. Menard ......... 233 



1. Introduction ......... 233 



2. Outline of submarine topography . ..... 235 



3. Summary of submarme topographic forms .... 277 



