The Mighty Deep 



tion of sea-shells upon high summits. It may be 

 also that the surface of the sea itself the general 

 level of the ocean has not been always the same. 

 It too may have risen and sunk ; not once only, 

 but many times. 



Between one and two hundred years ago there 

 was a theory that the sea had as a whole sunk 

 lower, on account of the enormous drying up of 

 its surface. Of course the surface does dry up 

 very much and very rapidly. Yet this deficit in 

 ocean-waters being met by equally enormous 

 down-pourings of rain and gifts of river-water, 

 evaporation will not serve to account for a 

 lowered ocean-level all over the earth. So the 

 notion had to be given up ; and in later years it 

 was looked upon as certain that the land must 

 have risen, and that the ocean-level must have 

 been changeless. 



Until recently this was regarded as estab- 

 lished ; but in the curious see-saw of scientific 

 theories the pendulum has begun to swing 

 back. 



Not all the way. That the land has risen in 

 parts, shaking its skirts free from ocean-tides, is 

 not doubted. Scientists are, however, maintain- 

 ing that while this is true, the other need not be 

 untrue. They hold that, while land in many 



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