LOWER SILURIAN FOSSILS. 47 



Brachiopods, with reference to the by no means 

 exalted bivalve shell-fish which forms its predo- 

 minant class. Such being the actual state of the 

 case, T must persist in describing even the fauna 

 of this age, which we now know was not the first, 

 as, generally speaking, such a humble exhibition 

 of the animal kingdom as we might expect, upon 

 the development theory, to find at an early stage 

 of the history of organization.* 



We now come to the Upper Silurians, where 

 new species of invertebrated animals appear, be- 

 sides a few obscure fishes. There is no appear- 

 ance, according to the Edinbiu"gh reviewer, of 

 a transition from the former species to the present 



* Objectors to the development theory have, in the eagerness 

 of counter-theorizing, committed themselves on the subject of 

 the Silurian fossils, in a way which they will yet feel to be ex- 

 tremely awkward. The I^'orth British Review we have seen 

 placing even fishes in the first fossiliferous rocks, grounding this 

 statement upon an authority which has been antiquated for fully 

 eight years — a vast period in the history of geology. The British 

 Quarterly Review is equally unfortunate. " The Author's 

 theory," says this writer, " requires that these animals should 

 be the lowest in the animal scale. But no argument can con- 

 vert a fish, with its back -bone, and highly-developed nervous 

 and muscular systems, into an animal of low organization." (!) 

 The dogmatic allegations of the Edinburgh reviewer on this 

 point are sufficiently exposed in the text. I have only further 



