294 THE BOTTOM OF THE SKA 



large for the kernel which it everywhere enveloped, 

 caved in, and thus the first heaving-up of mountainous 

 masses marked the end of a geologic period. Lands 

 rose above the waters, and marine deposits no longer 

 covered the entire globe. The constancy of the 

 ocean temperature, owing to the near neighbourhood 

 of igneous matters, rendered very feeble, or alto- 

 gether prevented, the formation of marine currents. 

 As the equilibrium gradually ceased to exist in the 

 liquid mass, owing to the constant growth and the 

 changes that were taking place in the earth's crust, 

 ocean- currents came into being. 



The atmosphere was, in its turn, modified by con- 

 tinual precipitations and despoiled of its vapour of 

 water, which went to elevate the level of the seas. 

 This operation again brought into existence atmo- 

 spheric currents. 



The crust of the earth still continuing to cool, 

 fresh collapses would take place, and fresh wrinklings 

 or foldings of the solid envelope already formed. 

 New mountains arose from the bosom of the waters, 

 new rendings of the soil gave free passage to the 

 igneous matters in the interior, and hence the great 

 extent to which volcanic matter is found spread over 

 the surface. By this time living creatures had ap- 

 peared, which at first were remarkable for the sim- 

 plicity of their structure and for the capability of 



