32 THE THEORIES OF EVOLUTION 



contended that all the transformations our earth 

 underwent in the past are easily explained by simple 

 phenomena such as can be observed in our days. 



Geologists following this path noticed traces of 

 rain drops in carboniferous strata, observed the in- 

 fluence of streams on the configuration of their banks, 

 the destruction wrought upon the shores by the action 

 of the sea, the erosion of glaciers, etc. Everything 

 confirmed the hypothesis that the earth's crust had 

 been formed gradually by the action of natural fac- 

 tors and that no special creative intervention was re- 

 quired in order to bring about such changes. 



At the same time, paleontological discoveries con- 

 tradicted certain positive statements of Cuvier's rel- 

 ative to the origin of man. Never, he said, would 

 we find the link between man and the other animals ; 

 never would we discover any fossil remains of pre- 

 historic man or of anthropoid apes. And after his 

 death, geologists unearthed fossil remains of the lat- 

 ter, then flint tools' used by the prehistoric man and 

 finally human skulls apparently inferior to that of 

 the modern man. Vestiges of the prehistoric man 

 appeared more and more frequently; more and more 

 frequently objects were found, dating from the pe- 

 riod when man's ancestors were being transformed 

 gradually into men. 



In another line of thought, in philosophy, Spencer 



