552 Notices of Memoirs—Professor W. S. Boulton— 
accurately to interpret the results of the surveyor’s work. There is 
so much to express that a single map will not always suffice. It 
may be desirable to show not only the outcrops of the strata at the 
present surface, but the thickness of the beds, and even the shape of 
a buried landscape or sea-planed surface, now unconformably overlaid 
by newer rocks. That the Geological Survey are alive to the 
importance of such work is shown by some of their recent publications. 
The memoir on the Thicknesses of Strata i the Counties of England 
and Wales, excluswe of rocks older than the Permian, published 
this year, is a most valuable compilation, bringing together officially 
for the first time a vast amount of useful fact, mainly from open 
sections and borings. May we not look forward to the time when 
the Survey can issue maps with ‘isodiametric lines’ showing the 
thicknesses in the case of important beds; for example, sheets of 
productive coal-measures, water-bearing beds, and so forth? In any 
case, we may confidently expect maps that will show by contours the 
shape and depth of those buried rock-surfaces, whether unconformities 
or otherwise, which limit strata of peculiar economic value. The 
Director of the Survey has already given usa foretaste in his valuable 
and suggestive maps of the Paleozoic platform of South-East 
England,’ and in the contoured maps of the base of the Keuper and 
of the Permian to the east of the Yorkshire, Nottingham, and Derby 
Coalfield, and the rock-surface below sea-level in Lincolnshire.’ 
Some of the new edition 1 in. colour-printed maps, excellent 
though they are, suffer by being overburdened with detail already, 
and we ought to consider whether it is not possible to issue maps of 
selected districts in series, as is done in the beautifully printed 
atlases of the United States Geological Survey, where each map of 
the series shows one particular set of features. .. . 
We have yet to realize that technical knowledge, of the highest. 
value to the country and obtained at great cost and labour, should be 
distributed as widely as possible, and at the lowest or even at a 
nominal charge. I would go further, and put much of the technical 
information in a simple and attractive form. We might even hope, 
for example, to eradicate the lingering superstition of the water 
divining-rod, which is still requisitioned by some public bodies. 
How admirably clear, simple, and direct is the information on water- 
supply in the little Survey memoir entitled Votes on Sources of 
Temporary Water Supply in the South of England and Neighbouring 
Part of the Continent, price 2d., evidently produced under the stress 
of War conditions, and all the better for it. 
During the last few months a series of much more important 
publications by the Geological Survey has appeared. I refer to the 
Special Reports on the Mineral Resources of Great Britain, of which 
some six volumes are completed. The Survey is to be congratulated 
upon starting a line of investigation and report which is a return to 
some of its oldest and best traditions. The Preface, by the Director, 
to the first volume of the series, that on the Tungsten and Manganese 
Ores, is illuminating and symptomatic, for it reveals a consciousness 
1 A. Strahan, Pres. Address to Geol. Soc., 1913. 
2 Mem. Geol. Sury., Thicknesses of Strata, pp. 88 and 110. 
