40 THE BIG-BONE LICK. 



red mud in the Bay of Fundy, which had just been formed 

 by sand-pipers ; and on examining an inferior layer of mud, 

 formed several tides before, and covered up by fresh sand, he 

 discovered casts of impressions similar to those made on the 

 last -formed layer of mud. Near the footsteps he observed 

 the mark of a single toe, occurring occasionally, and quite 

 isolated from the rest. It was suggested to him that these 

 marks were formed by waders, which, as they fly near the 

 ground, often let one leg hang down, so that the longest toe 

 touches the surface of the mud occasionally, leaving a single 

 mark of this kind. He brought away some slabs of the 

 recently formed mud, in order that naturalists who were 

 sceptical as to the real origin of the ancient fossil ornithich- 

 nites might compare the fossil products lately formed with 

 those referable to the feathered bipeds which preceded the 

 era of the ichthyosaurus and iguanodon. 



THE BIG-BON LICK. 



We will now cross the Alleghanies westward, where we shall 

 find a thickly-wooded country. As we proceed onwards, 

 entering Kentucky, we reach a spot of great geological interest, 

 called the BIG-BONE LICK. These licks exist in various parts 

 of the country. They are marshy swamps in which saline 

 springs break out, and are frequented by buffalo, deer, and 

 other wild animals, for the sake of the salt with which in 

 the summer they are incrusted, and which in winter is dis- 

 solved in the mud. Wild beasts, as well as cattle, greedily 

 devour this incrustation, and will burrow into the clay im- 

 pregnated with salt in order to lick the mud. In the Big- 

 bone Lick of Kentucky the bones of a vast number of masto- 

 dons and other extinct quadrupeds have been dug up. 



