338 SPARKS FROM A GEOLOGIST'S HAMMER. 



ground for the inference that all existing animals are 

 bound in a genetic system by the bonds of universal 

 cousinship. It is of no import that we revolt at the 

 thought. Perhaps the revulsion has no more rational 

 foundation than taboo among savages. Perhaps the rela- 

 tionship, on reflection, will enhance to a sublime degree 

 our comprehension of the system of organic life, and of 

 the unity of all the world under the method of one 

 intelligence. Perhaps it will appear that man's structure 

 was not embraced in the scheme of derivative origins. 

 Perhaps, if it was so embraced, he will be found to possess 

 some distinct elements in his psychic nature which cannot 

 be traced to lower existences. In any event, having felt 

 the force of the evidence, it is manly to stand by it, and 

 let the unity of truth determine the adjustment of the 

 consequences. 



We have, in the second place, what may be styled the 

 palceontological evidence. The discovered records of extinct 

 life upon the earth, it must be admitted, are extremely 

 defective, and offer many instances which, in the present 

 state of our knowledge, appear to conflict with the doctrine 

 of descent, though there are no facts irreconcilable with 

 it. That the record is incomplete, and must always remain 

 incomplete, is obvious from a few considerations. The 

 calcareous secretions of marine animals are the principal 

 relics preserved. All animals without hard secretions 

 have perished. The greater part of the hard secretions 

 of animals has been destroyed by the action of sea-water 

 and other agencies. Nothing of the terrestrial popula- 

 tions of the globe has been preserved except as chance 

 transported them into bodies of water to be buried be- 

 neath their sediments. In the oldest rocks, moreover, 



