46 THE PAST CONDITION 



long. This great beast had died and got buried in the 

 sand, the sand had gradually hardened over the bones, 

 but remained porous. Water had trickled through it, 

 and that water being probably charged with a super- 

 fluity of carbonic acid, had dissolved all the phosphate 

 and carbonate of lime, and the bones themselves had 

 thus decayed and entirely disappeared ; but as the 

 sandstone happened to have consolidated by that time, 

 the precise shape of the bones was retained. If that 

 sandstone had remained soft a little longer, we should 

 have known nothing whatsoever of the existence of the 

 reptile whose bones it had encased. 



How certain it is that a vast number of animals 

 which have existed at one period on this earth have 

 entirely perished, and left no trace whatever of their 

 forms, may be proved to you by other considerations. 

 There are large tracts of sandstone in various parts of 

 the world, in which no body 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 Con- 

 necticut 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 inter- 

 esting mammalian animals, and up to this time, if I 

 recollect rightly, there have been found seven speci- 

 mens of its lower jaws, and not a bit of anything else, 

 neither limb-bones nor skull, or any part whatever ; 

 not a fragment of the whole system ! Of course, it 



