EARLIEST REPTILES. 



235 



may be made out to be difficulties in the way of general- 

 ization. Passing to the particulars, a few land lacertilians 

 come first, whereas the first, according to my hypothesis, 

 ought to be marine forms, and linked to fish. He says 

 of this difficulty, that I have stated it feebly. Perhaps it 

 would have been well for his own credit that he had stated 

 it somewhat less confidently ; for before his sheets had 

 seen the light, a prospect had arisen of his affirmations on 

 this point being thoroughly falsified. In Silliman's 

 Journal, for April, 1845, is an account of sandstone sur- 

 faces pretty far down in the Carboniferous formation of 

 Pennsylvania, marked with the vestiges of terrestrial ani- 

 mals. Setting aside, in the meantime, one class of these 

 markings, which are said to indicate wading birds, we 

 have a variety of others plainly denoting reptiles. In 

 one group, the foot consists of a ball, with five toes radi- 

 ating from it in front. In another, the impression resem- 

 bles that made by a coarse human hand, with the rudiment 

 of a sixth toe at the outside. The reptilian families in- 

 dicated by these foot-marks have not yet been pronounced 

 upon, as far as I am aware ; but from the extreme resem- 

 blance of some of them to the vestiges of the labyrinth- 

 idon, there can hardly be a doubt that some of the order 

 batrachia are amongst them. If they prove wholly 

 batrachian, as is not unlikely, for we have living families 

 'with feet resembling the first group of vestiges, or even 

 if only a portion of them be certified as of this order, 

 where will be the lacertilians, and where the confident 

 counter-assertions of the Edinburgh reviewer? The ba- 

 trachia he has himself allowed to be a low order of rep- 

 tiles (p. 51.) They are so considered by all naturalists. 

 Might I not here, then, take my stand upon the fact of an- 

 imals, the lowest apparently of the reptile order, being now 

 found at the earliest point of time ? I might unquestion- 

 ably do so with a decided immediate advantage to my hy- 

 pothesis. It would in a great measure neutralize the 

 whole of the objections of the reviewer with regard to 

 the chronology of the reptiles. But I am, whatever he 

 may think of me, willing to read the book of nature aright. 

 I receive the fact as one liable any day to receive a new 

 aspect from fresh discoveries. In as far as it is so, it only 

 teaches that we are not to be too confident in drawing in- 

 ferences either for or against the theory of development 

 from the particular succession in which the orders of the 



