26 



BRUCE C. HEEZEN AND MARIE THARP 

 Table 1* 



(Surface area of world oceans 

 361 X 10«km-) 



105-123 



137-159 



* After Donn, W. L., Farrand, W. R. and Ewing, M. (1962). 



t Minimum volume after Crary (1960), maximum after Novikov (1960), estimates of 

 Antarctic ice. 



Ridge (Fig. 2). Gaps of over 200 miles must have existed between Faeroes and 

 Iceland and between Iceland and Greenland with prevaihng depths of 100 or 

 200 m. Thus, if a nearly continuous land bridge between Europe and Iceland 

 is required, it must be assumed that the Iceland-Faeroe Ridge has subsided 

 slightly more than 200 m in the last 200,000 years since eustatic lowering 

 alone is insufficient to account for the emergence of a land bridge during the 

 penultimate glaciation. Such a subsidence cannot be considered geologically 

 unreasonable, but the ultimate proof will lie in geological exploration of the 

 ridge and in the results of the study of North Atlantic biota. 



REFERENCES 



BucHER, W. H. (1952). Continental drift versus land bridges. In E. Mayr (ed.): The 

 problem of land connections across the South Atlantic, with special references to the 

 Mesozoic. Bull. Amei: Mas. Nat. Hist. 99, 93-103. 



Crary, A. P. (1960). Status of United States scientific programs in the Antarctic. T.G.Y. 

 Bull. 39, Amer. Geophys. Union Trans. 41, 521-532. 



DiETz, R. S. (1961). Continent and ocean-basin evolution by spreading of the sea floor. 

 Nature 190, 854-857. 



Donn, W. L., Farrand, W. R., and Ewing, M. (1962). Pleistocene ice volumes and sea- 

 level lowering. J. Geol. 70, 206-214. 



Ericson, D. B., Ewing, M., Wollin, G. and Heezen, B. C. (1961). Atlantic deep-sea 

 sediment cores. Geol. Soc. Amer. Bull. 72, 193-286. 



Ewing, J. I. and Ewing, W. M. (1959). Seismic refraction measurements on the Atlantic 

 Ocean basins, Mediterranean Sea, on the Mid-Atlantic Ridge and in the Norwegian 

 Sea. Geol. Soc. Amer. Bull. 70, 291-318. 



