70 DR. H. B. GUPPY. 
most of the three channels leading into the lagoon. Speaking 
generally, the knolls, reefs, and banks within or at the mouths of 
the lagoon of Digo Garcia appear to have shallowed rather than to 
have remained stationary, but there are not a’ few exceptions to this 
statement. With much that Dr. Guppy says in the latter half of 
his interesting paper, I agree very heartily. In particular I am 
pleased to see that he admits the co-operation of several agencies, 
viz., currents, food supply, tidal scour, solution, and the action of 
breakers as necessary for the formation of an atoll or barrier-reef. 
It is my conviction that a true solution of the problem is only to be 
found when all these agencies are taken into account. Dr. Guppy’s 
own observations are so good, and his reasoning is so convincing 
upon this subject, that I must refrain from criticising what I may 
call the individual part of his paper. 
His explanation of the great barrier-reef of Australia is admirable, 
and there can be no doubt that fresh investigations made on other 
reefs will yield valuable results, which I hope will confirm his 
views, and enable us to formulate a general law for this class of 
structures. 
By the Rev. Witu1Am Wyatt Git. 
Dr. Guppy, in his interesting paper on “Coral Islands and 
Savage Myths,” quotes a statement made by me several years ago 
before the Anthropological Society, that “the colonisation of the 
Hervey Group may not date back beyond five or six centuries,” 
adding, ‘‘that the origin of these living and upraised coral islands 
would, according to this view, be of a very recent date. This isa 
conclusion, however, which we cannot accept,” &c. 
I still adhere to my opinion as to the modern colonisation of the 
Hervey Group. The grounds upon which I base this opinion may 
be found, not in the legend of Mani, &c., &c., given in my “Myths 
and Songs,” but the long series of historical stories, commemorative 
songs, and genealogical tables given in my “Historical Sketches 
of Savage Life,”* published by the New Zealand Government in 
1878. No critic of that volume (and there have been many in the 
southern hemisphere), has attempted to set aside my conclusion. 
The question as to “the origin of these living and upraised coral 
islands” is not to be settled by traditions however interesting, but _ 
by the science of geology. I believe them to be several thousands 
* W. B. Whittingham & Co., 91, Gracechurch Street, E.C. 
