REVIEWS 483 
km. These facts lead him to conclude that the two atoll belts have 
subsided, while the two high-island belts have risen; in a word, that the 
region has suffered a gentle folding, the atolls growing upward in 
the faint synclines. ‘True-scale profiles show the exterior slopes of the 
atolls to vary from 30° to 69° down to depths of from 100 to 400 fathoms. 
It may be added that the prevailing absence of atolls in the deep seas 
inclosed by the islands of the East Indian archipelago is plausibly 
explained by the too rapid subsidence of the sea bottoms and of any 
islands that may have risen from their deeper parts in that very unstable 
part of the earth’s crust. 
W. M. D. 
Les Iles Wallis et Horn. (The Wallis and Horne Islands, Pacific 
Ocean.). Parle Dr. M. ViAtA. Bull. Soc. Neuchat. de Géogr., 
Vol. XXVIII (1919), pp. 209-83. With halftone plates and 
an outline map of Wallis, 1: 60,000. 
The author of the above-cited article served as resident physician 
on the islands, which are French possessions, from 1905 to 1909; _ his 
geographical descriptions are general; his notes on the natives are much 
more detailed. Wallis, northeast of Fiji, consists chiefly of a main 
island, Uvea, of volcanic origin, 18 km. long by 6 or 8 km. wide, and 
about 200m. inaltitude; but there are also nineteen small satellite islands 
close by, of which three are volcanic, and the others are of coral origin. 
About half of the latter stand on the fine barrier reef, which, about 100 m. 
broad and interrupted by only four narrow passes, encircles the main 
island. ‘The inclosed lagoon is from 2 to 5 km. wide, and is much inter- 
rupted by shoals: its depth is not stated. A well-formed fringing reef 
surrounds Uvea, so that canoes can reach the shore only at high tide. 
A wharf for larger vessels is built across the fringing reef at the chief 
village. While the low coral-sand islands are covered with luxuriant 
vegetation, the uplands of the main island have an infertile clayey soil 
and bear but scanty vegetation, chiefly ferns; except that a few cavities, 
interpreted as ancient craters and about 50 m. deep, have a richer 
growth; one such cavity contains a small lake. The uplands descend 
to an irregular shore line, where sand flats, often inclosing shallow 
lagoons of small size, afford the only cultivable ground; here the villages 
lie and here the coco-nut palm flourishes, yielding the most important 
commercial product of the islands; but rats abound and injure the crop. 
There are no streams, but springs emerge at the inner border of the 
sand flats. The southeast trade wind, blowing continuously and often 
