224 Reviews—Mineral Resources of Great Brita. 
been responsible for no less than 101 of the analyses now tabulated. 
So far as the geological conclusions are concerned, all the arguments 
put forward in the first edition are somewhat strengthened, and the 
net result of the revision is a greater precision in the location of the 
lines of iso-anthracitization in the charts for the various seams. In 
the letterpress we find additional comments by Dr. Pollard upon 
certain more modern methods of analysis introduced by American 
and other chemists since 1908, but for the sake of uniformity none 
of these has been adopted. In the last pages of the memoir 
Dr. Strahan allows himself to draw tentative conclusions concerning 
the physical geography in South Wales and Ireland in Carboniferous 
times, and we find it definitely suggested that it was some peculiarity 
of physical geography in South Wales and Ireland which led to the 
differentiation of the material in the coal-seams. ‘‘ As the coast-line 
retreated northward the area of anthracite coal shifted and kept pace 
with it,” and the rule ‘‘that each seam in any locality is less 
, anthracitic than its predecessors . . . is a necessary accompaniment 
of the formation of anthracite at successive intervals at a more or less 
constant distance from a retreating shore-line’’. 
Of the labour involved in the preparation of the memoir only 
those who have personal experience of quantitative analysis of 
coal are competent to judge. The general laws governing the 
‘‘ oradation into anthracite’? in South Wales have been made clear, 
and even allowing for the unique opportunities offered by a coal-field 
which is in course of active development over almost the whole of its 
extent, it may be fairly claimed that this is no small accomplishment, 
a result certainly to be accounted as of ‘‘ both scientific and economic 
value’’. What has been done for anthracite may be extended to 
other groups of sedimentary rocks, and if geologists who have 
adequate experience of the arts of chemistry, or chemists who have 
sympathy with the requirements of geology, can be persuaded to take 
up the work, further discoveries of equal scientific interest and of 
perhaps even greater advantage to the nation’s commerce should 
reward their efforts. To such workers we commend the second 
edition of the Survey memoir on the Coals of South Wales as a model 
worth following when they present their results. W. G. F. 
IJ.—Tue Gronogican Survey on THE Mrnerat Resources oF 
Great Brrrary. 
ee the stress of a protracted war it behoves belligerent countries to’ 
take careful stock of their resources. The special reports by the 
Geological’ Survey on the Mineral Resources of Great Britain, of 
which three volumes have appeared—the first (pp. 59, 1s.) on 
Tungsten and Manganese Ores, the second (pp. 93, 1s. 6d.) on 
Barytes and Witherite, and the third (pp. 57, 1s.) on Gypsum and 
Anhydrite—are timely and very welcome. Some legitimate surprise 
may perhaps be felt that such obviously useful publications had not 
been issued long ago, before the cloud of war loomed and broke, but 
in this country the State was ever chary of assisting and stimulating 
industry, and the Geological Survey constitutes no exception to the 
general rule of Government departments. It is remarkable that for 
