172 



SEA AND LAND 



and therefore has to fold. It is evident that wlien a continent 

 has beL^un its growth the tendency is for the upward arching 

 curve to continue growing in tliat direction, while the down- 

 ward flexures of the sea-bottoms in the same general way per- 

 sistently tend to grow deeper. It is easily to be conceived 

 that in such a movement of uprising land and downsinking 

 sea-floor we necessarily have a neutral or fulcrum point of 

 the motion, in the manner indicated by the diagram. The 



In diagrams I. and II. the lines a h represent the land before the movement, and a' b' represent the land 

 after the movement : s s the position of the shore-line ; // the pivotal points : /s the sea level. In dia- 

 ffram III. the curved line designates a shore, the line a b connecting pivotal points 2X /• p, the pivotal line 

 partly under the land and partly under the sea. 



neutral ])oint, or position of no motion, on a line extending 

 from the interior of the continents to the areas of the neigh- 

 boring sea-basin, may occupy either of three positions in 

 relation to the shore-line. It may be just at the coast, in 



