ii6 



RELICS OF PRIMEVAL LIFE 



mina and magnesia occupying a large place in the 

 mineralizing silicate. Fig. 24A gives two illustrations 

 of this— one a crinoidal stem from the Silurian of 

 New Brunswick, injected with a silicate of alumina, 



V/ \. 



#-«* 



I- 



wu 



V '^ 



mmmxryk 



Fig. 24 a. — {a) Joint of Crinoid injected with a Hydrous Silicate^ 



Silurian, Pole Hilly New Brunswick, (x 25.) 



{b) Spiral Shell injected with a Hydrous Silicate allied to Serpentine, 



near Llangwyllog, North Wales, (x 25.) 



iron, magnesia and potash ; the other a spiral shell 

 from more ancient perhaps Cambrian rocks in 

 Wales, filled with a silicate apparently more nearly 

 related to serpentine. Further examples will be re- 

 ferred to in an appended note. 



