xviii Note on Maps 



grossly distorted, and it has long been agreed generally that the 

 *'top" and "bottom," or polar regions, are less important and should 

 therefore receive the roughest treatment. And they do. The two- 

 inch bands across the top and bottom of this map together represent 

 a total area only a little larger than that of Africa! Nonetheless the 

 wider band between these two fairly represents the comparative 

 proportions of the remainder of the world. About fourth fifths of 

 this is covered by water, and it is this part that interests us. The land 

 masses, apart from some islands, are unimportant except for their 

 names and general disposition. 



On this map the most significant feature displayed, and, indeed, 

 almost the only one, apart from the positions of the major sperm- 

 whaling grounds, is the disposition of the oceans. Now, it must be 

 clearly understood that an ocean, such as the North Atlantic, is not 

 just the water area between Europe and Africa on the one hand and 

 North and South America on the other. True, this ocean is con- 

 tained within that body of water but an ocean is not just a body of 

 water; it is a very definite geographical entity; it has most precise 

 limits and a highly complex structure. Complete definition of an 

 ocean would require a large volume, but the salient facts may be 

 summed up as follows: 



There are five true oceans — the North Atlantic, the South Atlan- 

 tic, the Indian, and the North and South Pacifies, though the division 

 between the last two is arbitrary in that you may separate them in 

 any of four different ways according to the over-all criteria you 

 choose to employ for the definition of the boundaries of an ocean. 

 Then, there is a considerable mass of water at the top of the world 

 which is normally called the "Arctic Ocean." Actually, we do not 

 know whether it is a true ocean or just a vast sea, because we do not 

 know what types of deposits cover its floor over that portion which 

 lies below the permanent Ice-raft, and until we do know this, 

 we can only apply a theory that disturbs many geomorpholo- 

 gists. 



Briefly stated, this is to the effect that the earth is really a sort 

 of vast crystal and is trying to adopt a tetrahedral form — namely, 

 a three-sided pyramid with an apex at the Antarctic and a flat tri- 

 angular base around the North Pole. This would give us apices at 

 four points, as we actually have in the land masses of northeast- 



