EXPLANATIONS 



ders, we do not find .my decapedous Crustacea (crabs, &c.,) 

 though these could have lived wherever othe" mollusks 

 and Crustacea could. In fact, it is a scanty arti most de- 

 fective development of life ; so much so, that Mr. Lyeli 

 calls it, par excellence, the Age of Brachiopod3, with 

 reference to the by no means exalted bivalve shell-fish 

 which forms its predominant class. Such being the ac- 

 tual state of the case, I must persist in describing even 

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

 first, as, generally speaking, such an humble exhibition, 

 of the animal kingdom as we might expect, upon the de- 

 velopment theory, to find at an early stage of the history 

 of organization.* 



We now come to the Upper Silurians, where new spe- 

 cies of invertebrated animals appear, besides a few ob- 

 scure fishes. There is no appearance, according to the 

 Edinburgh reviewer, of a transition from the former spe- 

 cies to the present; but does he know the signs by which 

 such a transition could be detected ? I am aware of none. 

 He says the new species are sharply defined, that is, 

 strongly distinct; and so they may be, without any preju- 

 dice to the transmutation theory — as far, at least, as I un- 

 derstand it. And here he remarks that there are the 

 same difficulties in the way of this theory, "both in the 



* Objectors to the development theory have, in the eagerness of 

 counter-theorizing, committed themselves on the subject of the 

 Silurain fossils, in a way which they will yet feel to be extremely 

 awkward. The North 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 Re- 

 view is equally unfortunate. "The Author's theory," says this 

 writer, "requires that these animals should be the lowest in the 

 scale. But no argument can convert a fish, with its back-bone, 

 and highly developed nervous and muscular systems, into an an- 

 imal of low organization." (!) The dogmatic allegations of the 

 Edinburgh reviewer on this point are sufficiently exposed in the 

 text. I have only further to express my surprise at finding Dr 

 Whewell participating in the mere ignorance of the first two of 

 the above-mentioned journals. In the preface to a volume which 

 he has recently published, under the title of Indications of the 

 Creator, he meets my arguments with a crude and incorrect view 

 of the fossil history, commencing with this sentence — " Vertebrate 

 animals do exist in the Silurian rocks, from which the asserted 

 law [that of development] excludes them." The existence of a 

 non-pisciferous formation had been unknown to him. Many of 

 the objections made to the development theory, in obscurer quar* 

 ters, rest on errors of a similar kind. 



