XVI 



CONTENTS OF THE SECOND VOLUME. 



Structure, and Stratified Arrangement of Eocks now forming in Coral Eeefs- 



Siipposed Increase of Calcareous Matter in Modern 

 Epochs controverted— Concluding Eemarks p^^^ ^gg 



Lime whence derived 



CHAPTEE XLIX. 



FORMATION OF CORAL ]IEEFS. 



V 



Growth of Coral chiefly confined to Tropical Eegions— Principal Genera of Co 

 building Zoophytes— Their Bate of Growth— Seldom flourish at greater I)^^ft 

 than Twenty Eathoms— Atolls or Annular Eeefs with Lagoons— Maldive Isl ^ 

 Origin of the Circular Eorm— Coral Eeefs not based on Submerged Volca "^ 

 Craters— Mr. Darwin's Theory of Subsidence in Explanation of Atolls, Enei^^ • 

 ling and Barrier Eeefs— Why the Windward Side of Atolls highest— Subsidenc' * 

 explains why all Atolls are nearly on one Level— Alternate Areas of Elev^^ * 

 tion and Subsidence— Origin of Openings into the Lagoons— Size of Atolls Ini ' 

 Barrier Eeefs— Objection to the Theory of Subsidence considered— Composition 



I 

 I 



» 



PtATE ^ 



Plate V. 



Plate V 



I 



f 



Page; 



Page ! 

 folio win o- 



Kg. 12 



"\\'exford 



m one he 



Kg. 11 



^e see tin 



^■ige 3 1 

 Page 5- 



Pa 

 Pa 

 Pa 



ge o( 



geoc 



