282 MISCELLANEA. [Ch. XV. 



Nelson and other authors, and maintained that the facts ob- 

 served in them are opposed to the views of Darwin. Al- 

 though so far as I am aware, Darwin had no opportunity of 

 studying and considering these particular objections, it may be 

 mentioned that two American geologists have since carefully 

 re-examined the district — Professor W. N. Rice in 1884 and 

 Professor A. Heilprin in 1889 — and they have independently 

 arrived at the conclusion that Dr. Rein's objections cannot be 

 maintained. 



" The most serious objection to Darwin's coral-reef theory, 

 however, was that which developed itself after the return of 

 H.M.S. Challenger from her famous voyage. Mr. John Murray, 

 one of the staff of naturalists on board that vessel, propounded 

 a new theory of coral-reefs, and maintained that the view that 

 they were formed by subsidence was one that was no longer 

 tenable; these objections have been supported by Professor 

 Alexander Agassiz in the United States, and by Dr. A. Geikie, 

 and Dr. H. B. Guppy in this country. 



" Although Mr. Darwin did not live to bring out a third 

 edition of his Coral Reefs, I know from several conversations 

 with him that he had given the most patient and thoughtful 

 consideration to Mr. Murray's paper on the subject. He 

 admitted to me that had he known, when he wrote his work, of 

 the abundant deposition of the remains of calcareous organisms 

 on the sea floor, he might have regarded this cause as sufficient 

 in a few cases to raise the summit of submerged volcanoes or 

 other mountains to a level at which reef-forming corals can 

 commence to flourish. But he did not think that the admission 

 that under certain favourable conditions, atolls might be thus 

 formed without subsidence, necessitated an abandonment of his 

 theory in the case of the innumerable examples of the kind 

 which stud the Indian and Pacific Oceans. 



" A letter written by Darwin to Professor Alexander Agassiz 

 in May 1881, shows exactly the attitude which careful con- 

 sideration of the subject led him to maintain towards the 

 theory propounded by Mr. Murray : — 



" ' You will have seen,' he writes, * Mr. Murray's views on the 

 formation of atolls and barrier reefs. Before publishing my 

 book, I thought long over the same view, but only as far as 

 ordinary marine organisms are concerned, for at that time little 

 was known of the multitude of minute oceanic organisms. I re- 

 jected this view, as from the few dredgings made in the Beagle, 

 in the south temperate regions, I concluded that shells, the 

 smaller corals, &c, decayed, and were dissolved, when not 

 protected by the deposition of sediment, and sediment could 



