PART 11. CHAPTER XXV. 



303 



Scarcity of Lime in Metamorphic Rocks. 



ages, and thousands of feet thick, are devoid of fossils — how 

 certain strata may first have been deprived of a portion of their 

 fossils when they became semi-crystalline, or assumed the tran- 

 sition state of Werner — and how the remaining organic remains 

 may have been effaced when they were rendered metamorphic. 

 Some rocks of the last-mentioned class, moreover, must have 

 been exposed again and again to renewed plutonic action. 



