344 QUESTIONS. 



is said of leaf-scars ? What was the peculiar condition of the atmos- 

 phere up to the Carboniferous age ? 



227. What change was made in it during that age? How was it 

 done? State the comparison made in regard to this transfer from 

 the gaseous to the solid .state. What is said of the climate of this 

 age ? What was the character of Carboniferous scenery? 



228. What is said of the extent of the successive platforms of vege- 

 tation ? What change occurred in the scene when the accumulated 

 material was submerged for conversion into coal ? What is said of 

 the animals of this age ? 



229. What is said of the coral animals ? What of the crinoids 

 and sea-urchins ? 



231. What of the Crustaceans ? What of the Reptiles ? State 

 the facts about the Pottsville reptile. What is said of the fishes ? 



232. State in full what is said of the Lepidosteus and of the gar- 

 pike of the present age. What is said of the Mollusks ? What of 

 the Productus spinulosus ? 



233. What of the Spirifer ? From what does the Permian period 

 get its name ? What is said of the Permian strata in this country ? 

 What of them in Europe ? 



234. What are the Permian rocks in this country? What is said 

 of the Permian limestones of Europe ? What was the condition of 

 North America at the end of the age of Coal ? What is said of the 

 disturbances of the coal-measures ? 



235. What is said of the connection of metamorphosis with these 

 disturbances ? What of their being systematic ? What of their rate 

 of movement ? What of certain valuable results of metamorphosis at 

 this time ? What of the debituminization of coal ? What of denuda- 

 tion ? What of the differences of the forms of life in different ages ? 



236. When did vertebrates first appear? When reptiles? What 

 class of animals did not appear till after Palaeozoic time ? What is 

 said of the disappearance of animals? What of the destruction of 

 life at the close of the Carboniferous age ? 



CHAPTER XVII. 



236. What are the divisions of the age of Reptiles? Whence 

 comes the term Triassic ? Whence Jurassic ? 



237. What is said of the term Oolitic ? What of the term Creta- 

 ceous ? What is stated about the Cretaceous system in this country ? 

 State in full what is said of the Triassic rocks. What is said of the 

 localities in which they are the surface rocks ? 



238. Why is this system often called in Europe the Saliferous sys- 

 tem? How is the production of salt there in contrast with its pro- 



