THE OUTER REEF. 21 



coral growth, and where, consequently, the building force is 

 entirely removed from the influence of special conditions exist- 

 ing in the superficial layers of the water. We may not yet 

 have fathomed the true method of the formation of coral islands, 

 but such evidences as I was able to obtain at the Bermudas 

 failed to convince me of the erroneousness of the time-honored 

 theory of subsidence which was first formulated by the illus- 

 trious Darwin, and which has so long ministered to the wants 

 of the geologist, and still more failed to satisfy me with the de- 

 mands of the younger school of geologists, who, under the lead 

 of the venerable Duke of Argyll, have pinned to their standard 

 the now almost classical motto: "Conspiracy of Silence." 



I could not readily determine to what extent the ocean side 

 of the reef was more profuse in its coral growth than the in- 

 ner side. Seemingly there could not be much difference, for 

 the profusion of the inner life was such as to make it difficult 

 to conceive how it could have been measurably exceeded. 

 Probably in this regard the Bermudas form an exception to 

 the supposed general rule which defines a comparatively barren 

 area immediately back of the surf. Surely, we found nothing 

 of the kind here. 



I was also much impressed by the fact that there were here 

 no loose boulders of rock, such as it might have been assumed 

 would be thrown up by the disintegrating force of the breakers. 

 Everything was firm and compact, except along the margins, 

 where the growth of millepore formed veritable, but readily 

 destructible, chevaux-de-frise. Walking on this part is danger- 

 ous, since it is not always easy to determine how strong the 

 growth is, nor how soon one may find his way into one of the 

 numerous water- passages which honeycomb the mass. We had 

 experience of this danger in wading within the millepore 

 shallows of Devonshire Flatts. The absence of coarse debris 

 is, doubtless, in a measure, due to the small extent of land 

 exposed, and to the depth of water which covers the greater 

 part of the reef. A rise in the reef would probaby bring about 

 other conditions as was manifestly the case formerly but 



