26,5 



LETTER XVIIf. 



A MPHIBIOLITH I.... ..TORTOISE CROCODILE. 



1 HE Amphibiolithi form a very large and important class of fossils, and 

 of which our own country has produced some very interesting specimens. 

 It must, however, be to those of the larger kind that our attention must 

 be directed ; since, from their minuteness and extreme delicacy, the 

 remains of frogs, serpents, and of the smaller species of the genus Lacerta, 

 are very rarely met with, and then can hardly be expected to afford us 



anv real instruction. The remarks which I shall have to offer will be 



/ 



entirely confined to the Amphibia reptiles, since I know of no decided 

 instance of the mineralized remains of any of the A. serpentes. 



The fossil remains of the genus Testudo are rarely found, and seldom 

 in such a state as can yield any positive information respecting the ori- 

 ginal animal. Indeed, when we consider that the sections into which 

 this genus (Testudo) has been divided by Linnaeus, of the sea, the fresh 

 water, and the land tortoise, are distinguishable by the feet being like fins, 

 or palmated, or club-shaped, with nails, it will be seen that any distinc- 

 tion of this kind can rarely be made in the fossil remains of these animals; 

 since, except in the impression in schist, which will be presently men- 

 tioned, no traces of the feet are, I believe, to be found among their fossil 

 remains. 



It may not, however, be improper to observe here, that should any re- 

 mains of this part of these animals be found fossil, they will not serve, with 



VOL. III. M M 



