UNIT 



X 



THE EARTH AND ITS INHABITANTS 

 HAVE CHANGED THROUGH THE AGES 



Fig. 466 Removing the stone fro7fi aromid a rare fossil lizard which was found i?i 

 Utah. The work is being done by Mr. 'Norman H. Boss of the United States National 

 Mnsetim. Most of our knowledge of prehistoric animals and plants is gained from the 

 study of fossils. Our knowledge of fossils l.iclps Jis understand many things about the 

 flnimcils (tnd plants living today, (smithso^iian jNSTiTyTiON) 



