30 THE OCEAN RIVER 



apart. The separate granite blocks of the continents are sup- 

 posed to have drifted away from each other over the underly- 

 ing basalt in much the same way that objects will slowly move 

 on the plastic surface of apparently solid asphalt in hot 

 weather. It has been pointed out that the outlines of the 

 present-day continents fit together like a jigsaw puzzle, and 

 that the mid-Atlantic Ridge may have been left when the con- 

 tinents broke apart. But this is equally well in accord with the 

 description we have already given of a continental splitting 

 over a billion years earlier. 



Others have supposed that the ocean basins were formed at 

 a relatively late date by the sinking of former granite conti- 

 nents into the basalt beneath, thereby forming the ocean 

 floors. A number of geologists believe that, long after Pangea 

 was supposed to have split apart, there still remained a con- 

 tinental connection across the South Atlantic. Today there 

 are only a few islands, such as St. Paul, South Georgia, and the 

 Falkland Isles, and the submerged connecting ridges; but it is 

 said that until less than 50 million years ago there was here a 

 great continent, Gondwanaland, in which South America, 

 Africa, and Australia were joined. It remained so until the 

 earlier part of the Cenozoic, the geological era which is still 

 running its course today. At that time either the continents 

 drifted apart, or great masses of land sank to form the floors 

 of the Atlantic and Indian Oceans. While Gondwanaland was 

 in existence it is also supposed, by believers in the more recent 

 origin of oceans, that a second continent connected North 

 America with Europe, and that when this also foundered in 

 the Cenozoic there was left only the mid-Atlantic Ridge, the 

 Azores, Madeira, and — until early historical times some ex- 

 tremists say — the lost land of Atlantis. 



There are very few scientists today who will support the 

 extreme view that an Atlantic continent foundered, taking 

 with it an ancient civilization, in about 10,000 b.c. We are 



