410 CORAL AND CORAL REEFS 



vice versd, volcanoes ought not to be found in company 

 with atolls, but they ought to be found in company with 

 fringing reefs." And if you turn to Mr. Darwin's great 

 work upon the coral reefs, you will see a very beautiful 

 chart of the world, which he prepared with great pains and 

 labour, showing the distribution on the one hand of the 

 reefs, and on the other of the volcanoes ; you will find that 

 in no case does the atoll accompany the volcano, or the 

 volcano burst up among the atolls. It is most instructive 

 to look at the great area of the Pacific on the map, and 

 see the great masses of atolls forming in one region of it a 

 most enormous belt, running from north-west to south- 

 east ; while the volcanoes, which are very numerous in 

 that region, go round the margin, so that we can picture 

 the Pacific to ourselves a section of a kind of very shallow 

 basin shallow in proportion to its width, with the atolls 

 rising from the bottom of it, and at the margins the vol- 

 canoes. It is exactly as if you had taken a flat mass and 

 lifted up the edges of it ; the subterranean force which 

 lifted up the edges shows itself in volcanoes, and as the 

 edges have been raised, the middle part of the mass has 

 gone down. In other words, the facts of physical geography 

 precisely and exactly correspond with the hypothesis which 

 accounts for the infinite varieties of coral reefs. 



One other point, before I conclude, about this matter. 

 These reefs, as you have just perceived, are in a most 

 singular and unexpected manner indications of physical 

 changes of elevations and depressions going on upon the 

 surface of the globe. I dare say it may have surprised 

 you to hear me talk in this familiar sort of way of land 

 going up and down ; but it is one of the universal lessons 

 of geology that the land is going down and going up, and 

 has been going up and down, in all sorts of places and to 

 all sorts of distances, through all recorded time. Geologists 

 would be quite ri^ht in maintaining the seeming paradox 

 that the stable thing in the world is the fluid sea and the 

 shifting thing is the solid land. That may sound a very 

 hard saying at first, but the more you look into geology, 

 the more you will see ground for believing that it is not a 

 mere paradox. 



In an unexpected manner, again, these reefs afford us 

 not only an indication of change of place, but they afford 

 an indication of lapse of time. The reef is a timekeeper of 

 a very curious character ; and you can easily understand 



