LOWER SILURIAN FOSSILS. 



223 



limit his view of mankind to juvenile schools, he might 

 with equal rationality deny that there is any such thing in 

 the world as infants in arms. " We speak of what we 

 have seen," he might say, " and finding no specimens of 

 humanity under three feet high, we are weak enough to 

 bow to nature and believe that babes are a mere fancy." 



Even taking the English Lower Silurians as he and 

 others would have them taken, it still appears that these 

 rocks denote, generally, a low state of the animal kingdom. 

 It is customary for those who take opposite views to speak 

 of the creatures of this period as high — " highly-organized 

 Crustacea and mollusca" is the usual phrase. Some, in- 

 cluding the Upper Silurians in their view, tell us that the 

 first formation presents examples of the whole of the great 

 divisions, the fish being held as representing the verte- 

 brata. Of course this is only done through ignorance, or 

 for the purpose of deceiving. Where particulars are over- 

 looked, it is still customary to speak of the earliest fauna 

 as one of an elevated kind. When rigidly examined, it 

 is not found to be so. In the first place, it contains no 

 fish. There were seas supporting crustacean and mollus- 

 can life, but utterly devoid of a class of tenants who 

 seem able to live in every example of that element which 

 supports meaner creatures. This single fact, that only 

 invertebrated animals now lived, i3 surely in itself a 

 strong proof that, in the course of nature, time was ne« 

 cessary for the creation of the superior creatures. And, 

 if so, it undoubtedly is a powerful evidence of such a 

 theory of development as that which I have presented. 

 If not so, let me hear any equally plausible reason for the 

 great and amazing fact that seas were for numberless ages 

 destitute of fish. I fix my opponents doww to the consid- 

 eration of this fact, so that no diversion respecting high 

 mollusks shall avail them. But. this is not all. The Si- 

 lurian is an age, as were several subsequent ones, of only 

 marine animals. It is now incontestible, from a few 

 land-plants found in the Silurians of America, and a fern 

 leaf in our own, that there was dry land ; yet no trace of 

 a land animal appears for ages afterwards. Moreover, 

 though we have now a pretty full development of the 

 first sub kingdom, Radiata, we have but an imperfect ono 

 of the two next — namely, the Articulata and Mollusca. 

 Not to speak of the utter absence of freshwater and land 

 mollusks, and of such land articulata a? nsects and spi- 



