HI EXPEDITION OF THE "CHALLENGER" 109 



her turbulent youth, before we, her children, have 

 any knowledge of her. 



So far as the evidence afforded by the super- 

 ficial crust of the earth goes, the modern geologist 

 can, ex animo, repeat the saying of Hutton, " We 

 find no vestige of a beginning no prospect of an 

 end." However, he will add, with Hutton, " But 

 in thus tracing back the natural operations which 

 have succeeded each other, and mark to us the 

 course of time past, we come to a period in which 

 we cannot see any further." And if he seek to 

 peer into the darkness of this period, he will 

 welcome the light proffered by physics and 

 mathematics. 



