CHAP. X.] CRETACEOUS PERIOD. 195 



land areas of that period to have had a similar trend, at 

 any rate in the northern hemisphere, and to have spread 

 from east to west rather than from north to south like our 

 present continents. It is probable, therefore, as Professor 

 Prestwich suggested, 1 that a great northern continent 

 stretched across what is now the shallower part of the 

 North Atlantic Ocean, between Norway and Greenland, 

 forming a barrier which excluded the colder waters of the 

 Arctic seas, and allowed the Cretaceous ocean to have the 

 full benefit of the warmer currents from the south. 



1 Pres. Address to the Geol. Soc., 1871 ; " Quart. Journ. Geol. Soc.," 

 vol. xxvii. p. Ixviii. 



