148 FORMATION OF CORAL REEFS. 



CHAPTER XI. 



FORMATION OF CORAL REEFS. 



AMONG the astounding discoveries of modern 

 science is that of the immense periods which 

 have passed in the gradual formation of our 

 earth. So vast were the cycles of time preceding 

 even the appearance of man on the surface of 

 our globe, that our own period seems as yester- 

 day when compared with the epochs that have 

 gone before it. Had we only the evidence of the 

 deposits of rock heaped above each other in regu- 

 lar strata by the slow accumulation of mate- 

 rials, they alone would convince us of the long 

 and slow maturing of God's work on the earth ; 

 but when we add to these the successive popu- 

 lations of whose life this world has been the 

 theatre, and whose remains are hidden in the 

 rocks into which the mud or sand or soil of what- 

 ever kind on which they lived has hardened in 

 the course of time, or the enormous chains of 

 mountains whose upheaval divided these periods 

 of quiet accumulation by great convulsions, 

 or the changes of a different nature in the con- 



