hillJ A LESSON ON FOSSILS 397 



In the warm seas of the tropics we see coral reefs and atolls of 

 great depth. If we look through the queer tube with a glass 

 window at the end that is sometimes furnished with boats at 

 sea side resorts, we see the sea bottom covered with shells, corals, 

 and strange sea animals. If these were to become buried under 

 layers of mud or sand, they would die but their hard parts would 

 remain nearly undamaged; sometimes the soft parts are preserved 

 too, becoming hardened by the lime. Mud and sand are rock 

 material and if they were to become solid rock, as mud and sand 

 have become in past ages before man was, their remains would be 

 fossils. 



The remains of ancient plants and animals found in the rocks of 

 quarries on outcropping ledges are fossils. Even the tracks of 

 animals found in the rocks are fossils. Skeletons of animals 

 found in not very perfect rock, are fossils also. There are some 

 such rocks and fossils in the regions of the Wasatch Mountains in 

 Utah. 



How Fossils Have Made Land 



At the time when this little fossil shell was the home of a living 

 creature there were no men on the earth; no horses had galloped 

 over the prairies; there were not even any prairies, only a few 

 big islands in an ocean that covered the mud. So of course, there 

 were no dogs, no foxes even, nor any cats, nor any birds singing 

 in the trees. There was a big strip of land in what is now a part 

 of British America. Over the bottom of this immense ocean grew 

 great coral reefs; in its waters lived many kinds of sea animals; 

 queer fishes swam there and giant shell bearing animals moved 

 sluggishly on the sea-bottom, some having chambered shells like 

 the Chambered Nautilius, some with straight shells ten feet long; 

 there were trilobites too, ancestors of our lobsters, crabs and 

 shrimps, star fishes and their relatives called by the geologists, 

 who first studied and described them star lilies because they grew 

 on stalks. Such of these animals as had lime in their shells or 

 their skeletons, helped the coral to make the rocks that lie under 

 the soil of much of New York State and in other parts of the United 

 States. 



After a long time, geologic ages, the crust of the earth in wrink- 

 ling slowly lifted some of the sea bottom, with its coral reefs and 

 deposits of mud mixed with shell deposits, above the water and 



