Reviews and Book Notices. 355 
The identification rests chiefly with the photograph of two 
nestlings obtained by a friend. Any bird photographer knows 
that the slight difference in black and white between the Young 
Pied Wagtail and the young White Wagtail, could not be 
recorded by the camera. A slight exposure, or a light, or a 
dark-print, would make much above the difference. I have even 
seen photographs of Lesser Black-backed Gulls, taken at close 
quarters, that I could not differentiate from Herring Gulls. 
Therefore we can only dispose of this record as eminently 
unscientific. And, although I believe that the White Wagtail 
does nest sparingly in Yorkshire, yet we can only accept 
this Scarborough record as non-proven. 

ih 0 A aa 
Elements of Mineralogy, by Frank Rutley. London: Murby & Co., 
i916. Pp. xxii.+ 394, 3s. 6d. net. This handbook is too well known 
to need description. The fact that it has now reached its nineteenth 
edition is a sufficient guarantee of its worth. The present edition has been 
revised by Mr. H. H. Reed, and there is a lengthy introduction by Mr. 
G. T. Holloway. Northern students will find many references to minerals 
to be found in Yorkshire, Derbyshire, Durham, Cheshire, Nottinghamshire, 
Northumberland, Cumberland, the Cheviots and Isle of Man, 
The Birds of Britain: their Distribution and Habits, by A. H. Evans, 
M.A., F.Z.S. ete. Cambridge University Press, 1916. Pp. xii. + 275, 
4s. net. The author hopes that the book, ‘though primarily intended 
for school,’ may be found useful by those who require a short handbook 
which includes the results of the most recent observations, and is adapted 
to modern nomenclature. That it is such a ‘short handbook’ we admit, 
but we doubt whether, with all its latin names and classifications, etc., 
it will be in great demand in schools, The notes are certainly written in 
a pleasant style—the number of species dealt with is enormous, and there 
are plenty of illustrations. There is also a list of ‘occasional visitors ’ 
and a good index. Though the illustrations are taken ‘for the most part 
from nature,’ some at any rate, certainly seem to be photographs of museum 
specimens. 
Agricultural Geology, by R. H. Rastall. Cambridge, 1916: pp. x. + 
331, Ios. 6d. Mr. Rastall deals with Minerals and Rocks, Weathering, 
Transport and Corrosion, Sediments, Superficial Deposits, Soils, Water 
Supply and Drainage, and Geological Maps. The second half of his book 
is devoted to Stratigraphical Geology, in which rocks from Pre-Cambrian 
to Recent are reviewed. He concludes with a chapter on the Geological 
History of Domestic Animals, and there is a poor index, with which he has 
been helped. There are some remarkably clear diagrams, apparently the 
work of Prof. J. E. Marr. The frequent use of chemical equations gives 
the pages a forbidding aspect. For instance, ‘ Serpentinization is generally 
attributed to the action of’Carbon dioxide dissolved in water,’ which is 
explained by “ 2[2 Mg.O.Si.O.9] + C.0.9 + 2H20. = 3 Mg.O. 251.09 
2 H.20.+Mg.C.O.3. This will not appeal to many readers unless they 
are familiar with chemistry. We find no reference whatever to Marr’s 
recent book on a similar subject, and as the author covers so many sub- 
jects, we should have liked some reference to the old soil maps issued in 
the county agricultural surveys published by the Board of Agriculture 
over a century ago. These were largely the basis upon which Smith’s 
Geological map of 1815, and subsequent geological maps, were prepared. 
The price of the book seems sufficient. 
1916 Nov. 1. 
