Reviews—German South Polar Expedition. 85 
its consolidation, are of three sorts: (1) tourmalinization, as exemplified 
in luxulyanite and in the schorl-rock of Roche; (2) greisening, as seen 
at Criggan; and (3) kaolinization. The kaolinization or alteration of 
eranite to china-stone and china-clay is a subject discussed by 
Mr. MacAlister, supplemented by observations made by Dr. Flett. 
With regard to the kaolinization, Mr. MacAlister refers to the agency 
of magmatic waters containing carbon dioxide in solution and fluoride 
vapours. Dr. Flett remarks that the facts ‘‘ point to the probability 
that neither fluoric nor boric gases were the chief agencies of 
kaolinisation, and support Vogt’s hypothesis that carbonic acid was 
the principal, though probably not the only, gas involved’’. Many 
interesting particulars are given of the china-stone and china-clay, but 
it has not been found possible to mark on the map the areas over 
which they are exposed. Economic geology, indeed, receives ample 
treatment. ‘The chapter on mining, prepared by Mr. MacAlister, 
with numerous illustrative sections, contains full information of the 
workings for tin and copper ores, as well as silver-lead ores, red and 
brown hematites (for which Restormel was once famous), manganese 
ore, gold, uranium ore, etc. Of road-metals, the harder diabases and 
the calc-flintas (altered calcareous sediments in the Meadfoot Beds) 
are reckoned more durable than the elvans. 
Mr. Barrow has described some of the physical features and the 
indications he has found of the old Pliocene platform at about 430 feet 
above sea-level. There on flat moors, beneath peat, rainwash, and 
head, occur ferruginous gravels that have been worked for stream- 
tin, and these may possibly be of Pliocene age. The later Pleistocene 
and Recent deposits are described in detail, evidently by Mr. Ussher, 
but curiously enough his initials, appended to many paragraphs, have 
been omitted from this section as well as from the important chapters 
on the Devonian rocks. This is much to be regretted. 
Ii1.—Tuar Geruan Sourn Potar Exprprrion, 1901-1908. Vol. II, 
Heft V: Geography and Geology. pp. 63 and 3 plates. . Berlin, 
1909. Price 10 marks (8 marks to subscribers). . 
(Devrscue SupPoLaR-ExPEDITION, 1901-1903, im Auftrage des Innern 
herausgegeben von E. von Dryeatsxr, Leiter der Expedition. 
Il Bd. Geographie und Geologie, Heft V.) 
f{\HE present report is composed of four sections, dealing mainly with 
the islands of St. Paul and New Amsterdam in the Indian Ocean. 
The geography is dealt with by E. von Drygalski, the leader of the 
expedition, the geology by E. Philippi, the character of the rocks by 
R. Reinisch, and the plants and animals by E. Vanhoffen. According 
to Dr. von Drygalski, the islands of St. Paul and New Amsterdam are 
both volcanic and rest upon a common tapering base, which rises from 
about 8000 metres below sea-level. At a depth of 1500 metres this 
common source divides into two cones, which form the two islands. 
Both islands have a number of parasitic cones, but these do not 
constitute so striking a feature in the case of St. Paul as in New 
Amsterdam. The islands of Kerguelen and Heard on the one hand, 
and St. Paul and New Amsterdam on the other, also have a common 
