xxiv CONTENTS. 



PAGE 



Close of the Carboniferous Period 584 



In Foreign Countries 584 



Europe, 584. Thickness, 588. Igneous rocks and crustal 

 disturbances, 588. 



Other Continents, 589. Asia, 589. Africa, 590. Australia 

 and New Zealand, 590. South and Central America, 591. 



The Life of the Pennsylvanian Period 591 



I. The Plant Life 591 



The Coal Flora 591 



The Filicales, 593. The Cycadofilices (Pterido- 

 spermse), 595. The Equisetales (calami tes, horse- 

 tails), 596. The Sphenophy Hales, 598. The Lycopo- 

 diales, 598. Stigmaria, 600. The Cordaites, 600. 



The Distribution of the Carboniferous Flora 601 



Climatic Implications of the Coal-plants 603 



The influence of increased carbon dioxide on plant 

 growth, 605. 



II. The Land Animals 606 



The rise of the amphibians, 606. The marked 

 development of insects, 610. Spiders, scorpions, and 

 myriopods, 611. Land snails, 611. 



III. The Fresh-water Life 612 



IV. The Marine Life 613 



The progress of the fishes, 614. Changes in the 

 aspects of the mollusks, 615. Association of lingering 

 and advanced cephalopods, 615. The brachiopods, 615. 

 A new phase of the crinoids, 617. Almost the last of 

 the trilobites, 618. Other features, 618. 



CHAPTER XL 

 THE PERMIAN PERIOD. 



Formations and Physical History 619 



In the east, 619. In the interior, 621. In the west, 625. 

 Thickness, 625. Correlation, 625. 



The Foreign Permian 625 



Europe 625 



Lower Permian, 626. The Upper Permian, 628. Gen- 

 eral, 630. 



