36 MIGHTY ANIMALS 



And all these bones and leaves and twigs as they lay 

 at the bottom of the lake were covered up by other 

 mud that was washed into the water just as the 

 Dinosaur's bones had been covered. 



Through all this time the miracle was taking place. 

 For the weight of the water on the mud at the bottom 

 of the lake was causing that mud constantly to 

 become a thicker and harder mass. The enormous 

 pressure cemented the tiny particles together until 

 they turned to stone. And this is the way many 

 rocks in which bones are found buried were formed, 

 — by the long-continued pressure of water on mud, 

 or sand, or millions of tiny shells. Other rocks con- 

 taining bones were formed through different pro- 

 cesses equally mysterious, and always this marvelous 

 change was wrought in some way by the action of 

 water. 



But this changing of the mud into stone was not 

 all of the miracle that took place in the Dinosaur's 

 tomb. Not even the most delicate parts of his 

 skeleton were broken while this change was going on. 

 When he sank beneath the waves, this creature's 

 mouth had been partly open and at the time that his 



