230 Reviews—Every Boy's Book of Geology. 
impregnations along belts of joints in the Basement Schists. The 
chief introductions are auriferous pyrites, arsenical pyrites, and 
silica. These may be termed metasomatic deposits, in which the 
epidiorite is altered to a coarsely crystalline biotite-actinolite schist 
with auriferous sulphides. The outer sides of this rock merge 
gradually into the normal epidiorite. In some cases there is a thin 
_ quartz vein or succession of quartz lenses along the main joint or 
fissure, and gold may occur in these as well as in the schists. There 
appears to be a striking connexion between these veins and the 
acid and ultra-acid felsites mentioned above. 
The author has described the physical features of the district 
in some detail and with remarkable clearness. 
Every Boy’s Book or GEotocy: An InTRopUCTORY GUIDE TO 
THE STUDY OF THE Rocks, MINERALS, AND FOSSILS OF THE 
British Istes. By Artour H. TRupMAN and W. PERCIVAL 
WESTELL. pp. 1-315. R.T.S., n.d. [1920]. Price 6s. net. 
fe aim of this work is to arouse in young people an interest 
in the study of geology. The authors have made a judicious 
selection of the more attractive parts of the subject, and the book 
is written in plain and simple language, which should make it 
suitable for juvenile readers. The illustrations are numerous, and 
although sometimes a little crude, they serve the fundamental 
purpose of making the text easily intelligible. There is no connected 
account of stratigraphical geology, but the nature of the geological 
record is well shown by the chapters on “ Coal and Coal Mining ” 
and “‘ The Great Ice Age”’. 
SPECIAL REPORTS ON THE MINERAL RESOURCES OF GREAT BRITAIN. 
Vol XII, IRon OrkEs (contTp.): BEDDED ORES or THE LIAS, 
Oo.itES, AND Later Formations In Encianp. By G. W. 
LampuueH, F.R.S., C. B. Wepp, B.A., and J. Prinetz. Mem. 
Geol. Survey. pp. iv + 240, with 8 plates and 12 figures. 1920. 
Price 12s. 6d. net. 
eee publication of this memoir has been anticipated with much 
interest by all those concerned with the geology of iron-ores, 
since 1t contains an account of what are under modern conditions 
by far the most important. producing areas in this country. Of late 
years the Jurassic system has been responsible for almost exactly 
80 per cent of the total output of iron-ore in this country, a state 
of affairs which is mainly due to the recent developments in the 
manufacture of basic steel from phosphoric ores. This is precisely 
the same economic factor as led to the great prosperity of the 
German steel industry, which was almost entirely based on the 
phosphoric ores of Lorraine. During the War the production of 
basic steel in England showed a steady increase, although the total 
production of iron-ore even fell off a little. The great demand for 
