246 Chronicles of Science. [ April, 
shape, with this remarkable feature in addition, that the opening, 
which in coral islands is almost invariably on the windward side, 
is here on the leeward. ‘Taking all these facts into account, Dr. — 
Hochstetter arrives at the conclusion that one-half of the island is 
still beneath the sea, having been detached from the upheaved 
portion by a great dislocation. As soundings prove the existence 
of a considerable submarine plateau in the required position, which, 
if upheaved, would complete the pentagon, it seems tolerably clear 
that this explanation is the correct one. 
An interesting description of the geology of the Nicobar Islands 
follows, Dr. Hochstetter assigning their Tertiary deposits to the 
same period as those of Java (the Upper Miocene), with which he 
believes them to have been more or less connected ; later forma- 
tions, consisting of coral-banks raised to a greater or less height 
above the sea, connect that period with the present. An excellent 
memoir on Jaya is closely connected with the last; it contains 
descriptions of the chief physical features of the island, and espe- 
cially of its wonderful volcanoes. The stratified deposits are classi- 
fied under the heads Eocene and Miocene. ‘To the former belong a 
lower coal-bearmg group and an upper nummulite-limestone ; to 
the latter are referred a lower fossiliferous group, and an upper 
tufaceous group, with younger coral-banks, which may be of even 
more recent date. A description of the Stewart Atoll im the Pacific 
Ocean ends the geological part of this volume, and then follow two 
paleontological memoirs, one “On the Fossil Corals of Java,” by 
Dr. Reuss, and the other “On the Fossil Foraminifera of Car 
Nicobar,” by Dr. Schwager. 
Dr. Hermann von Meyer has published an important memoir 
“On Mastodon” in the ‘ Palaeontographica’ for last year, and a sum- 
mary of it in the ‘Neues Jahrbuch’ for December. He accepts 
Dr. Falconer’s subdivision of the genus, but at present discusses 
only two of the subgenera, namely, T’r2lophodon and Tetralophodon. 
Each of these he still further subdivides into two groups, one haying 
the valleys open, and the other having them closed by the adjoin- 
ing hill. In Trilophodon, Mastodon Ohioticus, M. Turicensis, and 
M. virgatidens (Meyer) belong to the former group ; and M. angus- 
tidens, M. Pentelicit, M. Humboldti, and M. Pandionis to the 
latter. In T'etralophodon Mastodon latidens has the valleys open, 
and M. Arvernensis, M. longirostris, M. Andiwm, and M. Peri- 
mensis have them closed. The subgenus Pentalophodon he does 
not discuss. 
We may here mention that the late Dr. Falconer’s collected 
Memoirs have been published, edited by Dr. Murchison, in two very 
thick octavo volumes. Of these, the first contains a reprint of the 
‘Fauna Antiqua Sivalensis, the plates also being in octavo, and 
interleaved with the descriptions ; and the second volume contains 
