XI PHENOMENA OF ORGANIC NATURE 351 



have entirely perished, and left no trace whatever 

 of their forms, may be proved to you by other 

 considerations. There are large tracts of sand 

 stone in various parts of the world, in which 

 nobody has yet found anything but footsteps. 

 Not a bone of any description, but an enormous 

 number of traces of footsteps. There is no 

 question about them. There is a whole valley in 

 Connecticut covered with these footsteps, and not 

 a single fragment of the animals which made 

 them have yet been found. Let me mention 

 another case while upon that matter, which is 

 even more surprising than those to which I have 

 yet referred. There is a limestone formation near 

 Oxford, at a place called Stonesfield, which has 

 yielded the remains of certain very interesting 

 mammalian animals, and up to this time, if I 

 recollect rightly, there have been found seven 

 specimens of its lower jaws, and not a bit of any 

 thing else, neither limb-bones nor skull, nor any 

 part whatever; not a fragment of the whole 

 system ! Of course, it would be preposterous to 

 imagine that the beasts had nothing else but a 

 lower jaw ! The probability is, as Dr. Buckland 

 showed, as the result of his observations on dead 

 dogs in the river Thames, that the lower jaw, not 

 being secured by very firm ligaments to the bones 

 of the head, and being a weighty affair, would 

 easily be knocked off, or might drop away from 

 the body as it floated in water in a state of de- 



