II Sept. Clocks retorded 



1600 1200 0000 



Time scale 

 10 Sept. 



9 Sept. 



8 Sept. 1954 



0000 130 1200 0800 

 _J L__J 



1000- 



B 2000- 



3000 



600 



Z6?°T g68°r-^?63°Ty 



Nauticol miles 



•6000 



Fig. 26. Magnetic sections across the central valley of the Mid-Atlantic Ridge. (After 

 Heezen et al., 1959, fig. 48.) 



SOOrM 



'>,400 



-400 



800 r 



60 80 



Nautical miles 



(b) 



40 60 



Nautical miles 



Figs. 27a and b. Magnetic profiles across the Red Sea. (T. D. Allan, unpublished.) 



