THE PEESEEVATION OF EOZOON. 



103 



that wlien decalcified tliese are most beautifully repre- 

 sented by tlieir casts, Dr. Hunt lias proved the filling 

 mineral to be a silicate of alumina, iron, magnesia 

 and potash, intermediate between serpentine and 

 glauconite. We have, therefore, ample warrant for 

 adhering to Dr. Hunt's conclusion that the Lauren- 







Fig. 25. tfotJit o/ a Crinoid, kaving its pores injected with a 



Hydrous Silicate. 



Upper SiltLTian. Limestone, Pole Hill, New Bruuswiek. Magnified 25 diameters. 



tian serpentine was deposited under conditions similar 

 to those of the modern green-sand. Indeed, indepen- 

 dently of Eozoon, it is impossible that any geologist 

 who has studied the manner in which this mineral 

 is associated with the Laurentian limestones could 

 believe ifc to have been formed in any other way. Nor 



