, 
OBJECTIONS TO THE THEORY OF SUBSIDENCE. 291 | 
inner channels whether subsidence is going on in the region 
or not, and are not evidence for or against either a move- 
ment downward or upward. Sandy Hook, the long, sandy 
point off the southern cape of New York harbor, has been 
undergoing (as the United States Coast Survey has shown) an 
increase in length, or rather variations in length, through the 
drifting of sands by an outside and an inside current; and 
this is no evidence that Prof. G. H. Cook is*wrong in his con- 
clusion that the New Jersey coast is slowly subsiding. 
3. Planting of corals on basements made and raised to the — 
right level by the growth of pelagic limestone or by other means. 
— The theory has been sustained by Mr. Semper, Dr. Rein, 
Mr. Agassiz, Mr. Murray, Dr. Guppy, and others, that since 
the growing calcareous deposits of the sea-bottom are slowly 
rising toward the surface by successive accumulations of the 
shells and other debris of pelagic species, they may have been 
built up locally in various regions of the deep seas (as they 
actually are now about some islands) until they were near 
enough to the surface to become next a plantation of corals; 
and that in this way, without any subsidence, atolls became 
common within the area of the tropical oceans. 
In support of this view, Dr. Guppy states that in elevated 
coral reefs of the Solomon Islands, one hundred to twelve 
hundred feet high, the coral reef rock forms a comparatively 
thin layer over impure earthy limestone abounding in fora- 
minifers, pteropods, and other pelagic organisms. Such ob- 
servations have great interest, but they only prove that in 
coral-reef seas corals will grow over any basis of rock that 
may offer where the water is right in depth and other cir- 
cumstances favor. They are not evidence against the subsi- 
dence theory,_but simply local examples under the general 
principle just stated. / Lr 
™. . : ” 
