REVIEWS AND BOOK NOTICES. 677 
took place, in all pr spt labs over the intermediate sea, called the 
“Coral Seas” where there are now a considerable number of atolls. 
The facts surveyed Rite us a long insight into the past, and 
exhibit to us the Pacific once scattered over with lofty lands, 
where now there are only humble monumental atolls. Had there 
n no growing coral, the whole would have passed without a 
record. These permanent registers exhibit in onene characters 
some of the oscillations which the “ stable” rth has since 
undergone.” 
While the island of Ponape is cited as affording evidence of a 
Be local subsidence in progress, the downward movement is not now 
general, and the period during which it took place “extends back 
to the Tertiary era, and perhaps still further back.” 
Geologists and paleontologists will be grateful for the grand 
generalization in the final chapter entitled, ‘Geological Conclu- 
sions.” Facts bearing in an interesting way on lithology are 
stated in the section on the ‘“‘ Formation of Limestones,” where the 
writer concludes that the “ reef-formations illustrate that not only 
coral conglomerates, or coral-rag may be made of corals, but also 
the very finest and most compact unfossiliferous limestones ; that 
fine compact limestone, as flint-like in fracture as any of Silurian 
time, is one of the most common of coral-reef rocks and is 
nothing but consolidated mud, or fine sand of coral origin.” 
_ These coral-reefs, which through subsidence became in some cases 
_ at least two thousand feet thick, are happily termed ‘beds of lime- 
stone with living margins,” the living part furnishing material for 
its horizontal extension outward, and also, if a slow subsidence in 
Progress, for its increase upward. ‘In the case of existing coral- 
reefs, there is yet no evidence that the species of the lower beds 
differ from those of the top. There is also no evidence, in any 
part of any ocean, that there is a set of cold water corals fitted to 
‘Commence a reef in deep water and build it up to such a level that 
another set of species may take it and carry it up higher ; the facts 
| thus far gathered are all opposed to such an idea. Should it be 
; er proved that the corals of the inferior beds differ in 
: species from those now existing, it will probably be found that 
= ule predecessors of those now living were also mano water 
^ oad so that the subsidence in any case was necessary.” 
"€ now come to the solution of some questions bearing on the 
: held by perhaps the majority of naturalists, that the 
“Present Ocean beds were formerly continents. So far as we are 
