AND THEIR DESCENDANTS 



and certainly in this environment became more and more 

 fitted for the business of living. 



In Mr. Henry R. Knipe's scholarly and well-informed 

 volume, Nebula to Man (J. M. Dent & Co.), to which 

 we are indebted not only for several of our illustrations 

 but for many extremely valuable suggestions, the struggle 

 for existence in the early ocean is well summed up : 



Thus through the hrine life manifold proceeds, 

 Impelled to higher states by growing needs ; 

 And all these early life-types in the seas 

 Will branch in time to many species ; 

 And some amid conditions too severe, 

 Must, after stress and struggle, disappear. 

 And when a species falls from Life's domain 

 It never gains a place on Earth again. 



We may speculate with some approach to certainty on 

 the general appearance of the earth in those days. There 

 was far more water on the surface of the globe ; the 

 land surfaces were small and infrequent. The seas may 

 have been shallower than those which we know, but they 

 were far greater in extent. There must have been far 

 more rain and a very much greater number of violent 

 storms arising from the constant condensation of the waters 

 by the rays of the sun. The sun was probably seen far 

 less often in those days, and there are some geologists 

 who believe the earth to have been perpetually covered 

 with cloud, as the planet Venus is now. 



Europe as a continent did not exist. A few islands 

 showed their heads above the waves where Germany and 

 Switzerland, Eastern France and Spain now stand. Scot- 

 land's rocky islets were probably visible, on the ex- 



205 



