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 chanoreless. 



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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