CONTEMPORARIES OF EOZOON 211 



stratified rocks, of the so-called primary system, 

 are only a backward prolongation of the chain of 

 fossiliferous strata ; the elements of which were de- 

 posited as oceanic sediment, like the clay-slates, 

 limestones, and sandstones of the Palaeozoic forma- 

 tions, and under similar conditions, though at a 

 time far more remote, and more favourable to the 

 generation of crystalline mineral compounds. 



" In this discovery of organic remains in the 

 primary rocks, we hail with joy the dawn of a new 

 epoch in the critical history of these earlier forma- 

 tions. Already in its light, the primeval geological 

 time is seen to be everywhere animated, and peopled 

 with new animal forms of whose very existence 

 we had previously no suspicion. Life, which had 

 hitherto been supposed to have first appeared in 

 the Primordial division of the Silurian period, is 

 now seen to be immeasurably lengthened beyond 

 its former limit, and to embrace in its domain the 

 most ancient known portions of the earth's crust. 

 It would almost seem as if organic life had been 

 awakened simultaneously with the solidification of 

 the earth's crust." 



Gumbel has described from limestones of Lauren- 

 tian age in various parts of Europe forms referable 



