SECTIONAL TRANSACTIONS.—C. 483 
Mr. F. W. SHOTTON. 
Examination of the cores of a group of three boreholes near Coventry led 
to the discovery of a typical ‘ Permian’ breccia band in the middle of the 
’ Allesley Conglomerate Division, well below the first appearance of breccias 
previously known in the Warwickshire coalfield. A detailed study of the 
constituents of all the pebbly horizons in the boreholes provided some data 
which has a bearing upon the mode of deposition of breccias and con- 
glomerates during the formation of the Midland Hercynian ranges. 
In the first place, the small quantity of pre-Cambrian material in the 
conglomerates is always angular, while any Silurian or Avonian fragments 
in the breccia are well rounded. Hence it is concluded that the production 
of a breccia or of a conglomerate depended mainly on the nature of the rocks 
that were undergoing erosion. 
Secondly, there is a deposition-cycle from conglomerates (mainly of 
Avonian pebbles) to a breccia of pre-Cambrian material and back to a con- 
glomerate. Now since it is likely that the cores of the Hercynian ridges 
would be mainly pre-Cambrian rocks, a general uplift with increased 
velocity of the rivers would lead to the distribution of pre-Cambrian pebbles 
in the intermont basins where previously only the more local Avonian and 
Silurian material had been transported. From this it is deduced that the 
observed cycle of deposition coincides with a period of uplift of the adjacent 
mountains, followed by their gradual lowering by erosion. 
Dr. BERNARD SMITH, F.R.S. 
In general red rocks contain less iron than non-red rocks. The colour is 
due to dehydration of ferric oxide, which takes place most rapidly in warm, 
moist climates under conditions usually productive of heavy vegetation. 
Residual soils of such regions may be distributed by streams without losing 
their ferric oxide. If subjected to powerful reducing action in swamps or 
the sea they usually lose their red colour. 
A residual soil underlies part of the Carboniferous Limestone of West 
Cumberland, and in the Carboniferous Basement Beds of part of North 
Wales red beds derived from residual soils give place upwards to marine 
lagoon-phase deposits. 
Most of our red beds were doubtless formed under desert or semi-arid 
conditions ; yet the question arises whether certain sediments laid down in 
comparatively arid tracts were not derived from uplands with residual soils 
formed under warm, moist conditions. We may, indeed, have to reconsider 
some of our views. 
In normal Coal Measure times the hinterlands may have supported 
a considerable upland flora and a red residual soil. ‘There would be oxida- 
tion of this vegetation in situ, and reduction of the ferric oxide of the soil 
swept into the swamps. 
In Upper Coal Measure times, when coal swamps were at a minimum, 
telative uplift of the land (of which there is internal evidence) probably 
brought about a freer drainage, entailing less chance of reduction of ferric 
oxide to the ferrous state. 
True aridity, however, seems to have set in towards the end of the period. 
. 
©. 
Dr. H. C. Versey. 
In the Penrith Sandstone two periods of coloration are found: i.e. 
pre-cementation and post cementation. . Part of the iron oxide is, apparently, 
precipitated from colloid solution, but much is detrital. ‘The impossibility 
