INTRODUCTION 27 



3. Lime carbonate (CaCOs). — -Many algae, as Corallina of- 

 ficinalis (a red alga) which it thickly coats with the white deposit, 

 Lithothamnion (a red alga) and Halimeda (a green alga) both 

 of which are most important in the building up of coral reefs ; 

 also the fresh-water alga, Chara, the principal agent in the for- 

 mation of marl. 



1. Distinguish between organic and inorganic matter. 



2. What is protoplasm ? 



3. Give three differences between plants and animals. 



4. What are the two chief conditions for the preservation of 

 an organism in the fossil state ? 



5. Name three kinds of deposits in which organisms may 

 become buried and thus preserved. 



6. What is amber ? loess ? 



7. Draw a diagram illustrating terrestrial and seashore 

 deposits and indicate the most favorable of all localities for 

 the preservation of fossils. 



8. Mention an example of a recent flood plain deposit in the 

 United States; of -a fossil flood plain. What kinds of fossils 

 are we most apt to find there ? 



9. Give an example of a fossil lake deposit and the kind of 

 fossils for which it is noted. 



10. Define and classify fossils. 



11. What are the chief minerals concerned in fossilization ? 



12. How^ may the entire bodies of animals at times be pre- 

 served ? 



13. Describe the process by which {a) a leaf is preserved and 

 fossilized ; {b) a clam shell ; (c) a bone ; {d) the burrow of a 

 worm ; {e) a jelly-fish. 



14. Explain by diagram the formation of an external and an 

 internal mold ; of a cast. 



15. Why does an injury to the mantle affect the shell? 



16. How may we judge of the shape of a vertebrate animal 

 merely by its skeleton ? 



17. What changes in color does a shell undergo during fossili- 

 zation ? 



18. Mention three examples of "fossils" due to inorganic 

 agencies ; three of pseudo-fossils. 



19. What are index fossils? Describe their bearing on geo- 

 logic and evolutionary problems. 



