v.] THE LIME IN THE MORTAR. 119 



coral, the whole is setting, as cement sets, into rock. 

 And what is this ? A long bank of stone standing up 

 as a low cliff, ten or twelve feet above high-water 

 mark. It is full of fragments of shell, of fragments of 

 coral, of all sorts of animal remains ; and the lower 

 part of it is quite hard rock. Moreover, it is bedded 

 in regular layers, just such as you see in a quarry. 

 But how did it get there ? It must have been formed 

 at the sea-level, some of it, indeed, under the sea ; for 

 here are great masses of madrepore and limestone 

 corals imbedded just as they grew. What lifted it up ? 

 Your companions, if you have any who know the 

 island, have no difficulty in telling you. It was hove 

 up, they say, in the earthquake in such and such a 

 year; and they will tell you, perhaps, that if you 

 will go on shore to the main island which rises inside 

 the reef, you may see dead coral beds just like these 

 lying on the old rocks, and sloping up along the 

 flanks of the mountains to several hundred feet above 

 the sea. I have seen such many a time. 



Thus you find the coral being converted gradually 

 into a limestone rock, either fine and homogeneous, 

 composed of coral grown into pulp, or filled with corals 

 and shells, or with angular fragments of older coral 

 rock. Did you never see that last ? No ? Yes, you 

 have a hundred times. You have but to look at the 

 marbles commonly used about these islands, with 

 angular fragments imbedded in the mass, and here and 

 there a shell, the whole cemented together by water 

 holding in solution carbonate of lime, and there see 

 -the very same phenomenon perpetuated to this day. 



Thus, I think, we have got first from the known to 

 the unknown ; from a tropic coral island back here to 



