THE MESOZ01C AGES. 233 



only with a niggardly hand on their successors! 

 Nature gives us no explanation of the mystery. 



" From scarped cliff and quarried stone, 

 She cries ' A thousand types are gone.' n 



But why or how one was taken and another left she 

 is silent, and I believe must continue to be so, because 

 the causes, whether efficient or final, are beyond her 

 sphere. If we wish for a full explanation, we must 

 leave Nature, and ascend to the higher domain of the 

 Spiritual. 



11* 



