550, b 



THE 



JOURNAL OF GEOLOGY 



JULY-AUGUST, 1894. 



THE ORIGIN OF THE OLDEST FOSSILS AND THE 

 DISCOVERY OF THE BOTTOM OF THE OCEAN. 



In the Origin of Species Darwin says that the sudden appear- 

 ance ot species belonging to several of the main divisions of the 

 animal kingdom in the lowest known fossiliferous rocks, is at 

 present inexplicable and may be truly urged as a valid objection 

 to his views. 



If his theory be true, he says that "it is indisputable that 

 before the lowest Cambrian stratum was deposited long periods 

 elapsed, as long as, or probably far longer than the whole interval 

 from the Cambrian age to the present day ; and that during these 

 vast periods the world swarmed with living creatures. " Here," 

 he says, "we encounter a formidable objection; for it seems 

 doubtful whether the earth, in a fit state for the habitation of 

 living creatures, has lasted long enough." "To the question 

 why we do not find such fossiliferous deposits belonging to these 

 assumed earliest periods prior to the Cambrian system I can give 

 no satisfactory answer." 



On its geological side this difficulty is even greater than it 

 was in Darwin's day, for we now know that the fauna of the 

 lower Cambrian was rich and varied ; that most of the modern 

 types of animal life were represented in the oldest fauna which 

 has been discovered, and that all its types have modern repre- 

 sentatives. The palseontological side of the subject has been 

 ably summed up by Walcott in an interesting memoir on the 

 oldest fauna which is known to us from fossils, and his collection 

 Vol. II., No. 5. . 455 



