98 FOUR-FOOTED AMERICANS 



" Of course in climbing this tree we shall only find 

 the living jMamnnils, the extinct species belong to an- 

 other branch of study." 



"What are 'stinct animals ? " asked Dodo. 



"Gone out ones, I guess," said Rap, "because 'stin- 

 guishing a candle means putting it out." 



" Alake the word extinguish and you will be perfectly 

 right, my boy," said the Dcjctor. 



" I suppose the ones that are dead looked like the 

 live ones, didn't they ? " asked Dodo. 



" By extinct animals the Wise Men mean not merely 

 those that are dead, but those that lived so long ago 

 that even their exact pattern has disappeared from the 

 earth, better designs having* replaced them." 



" Then how does anybody know about them ? " 

 asked Rap. " By reading in books, I suppose." 



" These animals had passed away before there were 

 any books, and before man, as we know him, was living 

 on the earth ; so all we can know about them must be 

 learned from the skeletons that are found buried be- 

 neath tlie earth, and in the rocks and beds of old-time 

 clay and silt. The study of these bones is called 

 Palaeontology." 



" How could their bones get into hard rock?" asked 

 Rajj and Nat almost together. 



" That question has a very long answer, and belongs 

 to the stciry rif \\hen the earth was young : but it will 

 help you to remember this much : — 



" Tlie earth \\us once a fiery ball of gases like the sun. 

 The time came when it was needed by the Mind that 

 plans and sets everythijig in motion, and He began to 

 develop it by degrees as He does everything ; for vsx 



