268 Fossil bones in Georgia. 



They all have marine shells adhering to them, on the frac- 

 tured surfaces as well as the others, a circumstance which 

 seems to show that their comminuted state is not owing to any 

 violence used in obtaining them. What could have occasion- 

 ed it, it is difficult to conjecture, and it appears the more re- 

 markable, when we consider their extraordinary hardness. 



I intend to confine my remarks to two or three of these 

 pieces, whose peculiar conformation renders them of the great- 

 est utility for the comparison we have in view. The first of 

 these are the tibia and fibula, which in this animal form in 

 fact but one bone. 



Perhaps there is no part of the skeleton, after the head, 

 which was more useful for our purpose than this. It is, 

 unfortunately, broken into three pieces, which when brought 

 together, form nearly the entire bone. The parts deficient 

 are, a large piece from one side of the upper extremity of the 

 tibia, including the cavity for receiving the inner condyle of 

 the femur, and a small piece from the lower extremity of the 

 fibula. The other articulating surface of the upper extremity, 

 which is flat, remains very entire, as well' as all the lower ex- 

 tremity of the tibia. Upon comparing the bone in this state, 

 with the minute description of Bru, and with the figures re- 

 cently published by Pander and D'Alton, the resemblance is 

 nearly perfect. The only disagreement that 1 can perceive 

 is, that the bone from Georgia has not the suture between 

 the tibia and fibula at their lower extremities, which is repre- 

 sented in those figures. The union is as perfect at this ex- 

 tremity as at the upper, so that they form but one bone, with 

 a large foramen in the middle. The disappearance of the 

 suture may however be accounted for, by supposing the in- 

 dividual from Georgia to have been an older animal. 



This bone belonged to the left side, as appears from the 

 deep groove near the lower extremity, probably for the ten- 

 don of the tibialis posticus muscle. This beingturned behind, 



