68 DR. H. B. GUPPY. 
and that sediment is carried for 20 or 30 or 100 miles and would 
tend to form the reef. In the atolls in the middle of the ocean, and 
not in the vicinity of large groups of volcanic islands, at a distance 
of 500 or 1,000 miles, it is difficult to imagine how the sediment 
would be sufficiently raised to build these volcanic peaks up to the 
surface. Being some distance away from the large islands there 
is no débris brought down to cover the peak. In that way 
Mr. Buchanan’s idea is that in the open sea the place of this 
sediment would be taken by the deep-sea corals. With regard to 
Captain Wharton’s remarks, I must allow his correction as 
regards the width not being greater at the northern portion of 
the east coast than a little lower down, but it seems strange 
that this should increase and widen where the _ barrier-reef 
begins. Then, as regards the cause of the ledge widening 
out, this is produced by the barrier-reef gradually going on. 
According to Mr. Murray’s idea, the reef would form on the 
edge of the ledge and would advance on the edge of the ledge 
seawards, so that the excess of this ledge over the lower part would 
represent the outer growth of the reef. I wanted to make a 
remark about the manner in which Mr. Darwin formed his original 
view of coral reefs. It was simply, no doubt, because he had at 
his disposal no evidence,—in fact, there,is not a single possible 
explanation of the origin of coral reefs in his book. His views on 
the subject are all objected to because he had not the evidence 
necessary to support them. The starting-point of Mr. Murray’s 
view, the covering of these volcanic peaks and the lifting up of 
sediment, was simply objected to because there was then no evidence 
in regard to it. With reference to what Mr. Hudleston has said 
about the thickness of coral reefs, that I looked upon as the prin- 
cipal point of the discovery in the Solomon Islands. According to 
Mr, Darwin’s theory, if this coral rock were formed by the sinking 
of the sea bottom, you would have a tremendous thickness in a 
certain time, 2,000 or 3,000 feet ; but, if they were not caused by 
this sinking, but were caused by the other theory, you would only 
have a thickness of coral reef of not more than 200 feet, so that it 
is quite incompatible with any movement of the sinking of the sea 
bottom. 
The meeting was then adjourned. 
