372 C0BAL8 AND CORAL ISLANDS. 



in the ocean of many granitic mountain chains, they do teach 

 that there are long ranges, or lines, of volcanic ridges and 

 peaks, and some of these may be among the discoveries of 

 future dredging expeditions. A range of deep-sea cones, or 

 sunken volcanic islands, would be as interesting a discovery 

 as a deep-sea sponge or coral, even if it should refuse, ex- 

 cepting perhaps a mere fragment, to come to the surface in 

 the dredge. 



We may also accept, with some confidence, the conclusion 

 that atolls and barrier reefs originated in the same great bal- 

 ance-like movement of the earth's crust that gave elevation 

 and cold, in the Glacial era, to high-latitude lands. If so, the 

 tropics and the colder latitudes were performing their several 

 works simultaneously in preparation for the coming era ; and 

 it is a gain to us in our contemplations, that we hence may bal- 

 ance the beauty and repose of the tropics, through all the pro- 

 gressing changes, against the prolonged scenes of glacial deso- 

 lation that prevailed over large portions of the continents. 



