THE EARLIER FORMS OF LIFE. 



267 



and only silica remains, the rhomboidal pieces being the only remnants 

 of the original structure. The Eozoon has not been so completely 

 fossilized as in the example of coniferous wood. The cell-wall and 

 supplementary skeleton still retain much of the original lime, while 

 the animal part has been entirely replaced by serpentine or some other 

 mineral. Subsequent pressure or desiocation has produced cracks in 

 the mass, which have been filled with an asbestus-like mineral of silky 

 lustre, and this has sometimes been confounded with some part of the 

 animal by objectors. a l 





A ^ 



1 s* <>*?* 



^>2? : s 



rc\^Qi\i: 



^ 



"i. 



V _:# 



Ml 





Mjmn 



wmM^ 





M* o 



-^iipgp 



Fig. 5. Canals of Eozoon, highly 

 magnified. 



^*iS!5 



Fig. 6. Coniferous Wood, illustrating Fossil- 

 ization. 



a, Partially mineralized, the white spaces being sil- 

 ica, the black vegetable matter ; b. Vegetable 

 matter removed by decomposition, leaving out- 

 line of the forms of the original pores. 



Few special subjects have been so carefully studied as the genuine- 

 ness of Eozoon. The treatises of Logan, Dawson, Carpenter, and 

 Hunt, admirably set forth every possible phase of geological position, 

 intimate zoological structure and affinity, mineral character both ori- 

 ginal and derived, and the conditions of origination. The elaborate 

 papers of the objectors, Messrs. King, Kowney, Carter, Burbank, and 

 others, show what the weaker positions are, and have enabled the advo- 

 cates to satisfactorily fortify the less defensible points of their argu- 

 ments. Every new discovery seems to aid the defenders, while the 

 philosophy of evolution is in harmony with the existence of a long 

 Eozooic age where the predominant life is scarcely elevated above the 

 working of crystalline forces. 



HuEOisriAisr Life. Gilmbel has described a species of Eozoon from 

 the supposed Huronian rocks of Bavaria. In this country Billings 

 has mentioned the occurrence of an Aspidella and Arenicolites from a 

 series of Newfoundland rocks called " Intermediate," most probably 

 of this age. The Aspidella bears some resemblance to the limpet-shell 

 or Patella, while it may have been some variety of crustacean. The 

 Arenicolites is a petrified worm-burrow. 



But the specimens of greatest interest are those brought to light 

 the present year by Mr. George W. Hawes from the Huronian of 



