Revieiu of Recent Geological Literature. 1 2 1 
includes, besides the discussion of the optical characters of crj'stals, a 
more elaborate discussion of their geometric characters. 
Luquer's work is different from all these in that it defines solely 
microscopic petrography, and does it in good style and order. It also 
enumerates the usual rock-forming minerals, giving their microscopic 
characters in rock-sections. It describes the manner of preparing 
rock-sections, and of treating them by simple chemical and mechanical 
tests, and adds a concise chapter on the micro-chemical methods of 
Boricky and Behrens. It also contains a tabulated scheme, or "key," 
for the determination of minerals, based, in the first instance, on their 
comparative double refraction. 
The book is elementary, and it could be criticised, but its place 
has not been filled by any of its predecessors. If it were more full in 
its own descriptions, instead of referring to other text-books, it would 
be better, because in making use of this book the student is also, in 
some instances, required to have several others at hand. But thes^e 
.additions would enlarge the volume so as to make it, what it does not 
claim to be, a full treatise on microscopical petrography. 
N. H. w. * 
77?.? Islands and Coral Reefs of Fiji. By Alexander Agassiz. 
Bulletin of the Museum of Comparative Zoology at Harvard College, 
vol. xxxiii; 167 pages, with 120 plates. Cambridge, Mass., May, 1899. 
This admirable volume, with its copious plate illustrations (charts 
sections, and photographic views), and 45 figures, mostly of scenery, 
in the text, gives a very thorough description of this island group, 
which the author examined in detail in 1897 and 1898, mainly for the 
purpose of determining the conditions of origin and growth of coral 
islands and reefs. He writes: "The islands of the whole group have 
been elevated, and since their elevation have, like the northern part of 
Queensland, remained nearly stationary, and exposed to a great and 
prolonged process of denudation and of aerial and submarine erosion, 
which has reduced them to their present hight. The submarine plat- 
forms upon which the barrier reefs have grown are merely the flats left 
by the denudation and erosion of the central island, while the atolls 
are similar flats from the surface of which the islands have at first dis- 
appeared and the interior parts of which have next been removed by 
the incessant scouring of the action of the sea, the ceaseless rollers 
pouring a huge mass of water into the lagoon, which finds its way out 
of the passages leading into it or over the low outer edges of the 
lagoon. These atolls and islands, surrounded in part or wholly by 
encircling and barrier reefs, have not been built (as is claimed by Dana 
and Darwin) by the subsidence of the islands they inclose. They are 
not situated in an area of subsidence, but on the contrary in an area 
of elevation. The theory of Darwin and Dana is therefore not appli- 
cable to the Fiji islands My observations in Fiji only empha- 
size what has been said so often, that there is no general theory of the 
iormation of coral reefs, either of barrier reefs or atolls, applicable to 
