310 TRANSACTIONS OF SECTION CG. 
2. The Distribution of Radium in the Rocks of the Simplon Tunnel. 
Ly Professor J. Jory, 8e.D., F.RS, 
The principal classes of material which enter into the composition of the massif 
of the Simplon are: (a) The Jura-Trias sediments, lithologically often much 
alike and much interfolded; (4) the Palzozoic crystalline schists; and (ec) the 
gneiss of Monte Leone and the Antigorio gneiss, both stated to be of Archzean 
age. These rocks throughout contain radium, and for the most part in quantities 
much above what hitherto has been ascribed to sedimentary or igneous rocks. 
Some thirty-six typical samples, taken from various points in the tunnel, have 
been examined. The poorest in radium are certain anhydrite rocks. Certain 
amphibolite schists go very high. The Antigorio gneiss rises from 105 x 10- 2 
and 8:0x10-” grams radium per gram of rock at the Italian entrance to 
23:7 x 10-¥ at 4000 metres inwards. Some of the Archean gneisses yielded very 
high results. 
Such quantities of radium if generally distributed throughout the rocks of 
the massif would be sufficient to disturb any forecast of the temperature 
which under normal conditions would be encountered at the level of the tunnel. 
It is suggested that the radium was in fact the source of the discrepancy between 
the predicted and the observed rock temperatures, 
As it is improbable that these results are unique and apply only to this 
particular sedimentary accumulation and locality, they appear to point to hitherto 
unsuspected quantities of radium (and its parent elements) in the immediate 
surface materials of the earth. It seems impossible to avoid the conclusion that 
these elements were precipitated along with the sediments entering into the 
composition of the massif, The question then arises whether the accumulation 
of such quantities of radioactive elements may not enter as a factor in the events 
attending mountain-building, It can be shown that an area of sedimentation 
whereon has been accumulated some 10,000 metres of sediments, having a richness 
in radium comparable with the Simplon rocks, must necessarily become an area 
of greatly lessened crust-rigidity, and would hence become the probable site of 
crust-flexure under tangential compressive stress. 
Further investigation will be required before such views can be generalised 
and the importance of radium as a source of instability of the earth’s crust be 
determined. Apart from any speculations as to the influence of radium as the 
cause of an energetic substratum, the shifting of radium and its parent elements 
by denudation must be regarded as a convection of thermal energy, and this 
convection, if the quantities involved are sufficient, must, under the conditions 
referred to above and the unceasing action of denudation, become rhythmic in 
operation, and at the same time must result in shifting the areas of high 
temperature and crust-weakness from age to age as the site of sedimentary 
accumulation changes, 
3. On the Pisolitic Iron Ores of Wales. By W.G. FEARNSIDES. 
The first part of the paper discussed the occurrence of the well-known iron 
ores of Caernarfon aud Merioneth, and showed that, though they have been taken 
by various writers as marking a well-constituted subdivision of the Tremadoc 
slates, they are really of the nature of fissure phenomena, and may occur at almost 
any horizon. 
The various worked exposures seem always to agree in the following par- 
ticulars :— 
1. They are associated with the occurrence of large hypabyssal or minor 
plutonic intrusions of sill-like habit, and occur among stratified rocks along the 
limit of the sill’s metamorphic area. 
2. They occur in more or less lenticular masses, of no considerable lateral 
extent, often heaped together, and separated by crushed shale partings in a way 
which may suggest bedding, but often thinning out, yet maintaining a linear 
arrangement across considerable tracts of country. 
