FROM THE LOWER CARBONIFEROUS OF NORTH WALES. 273 
and the Lake-district was due to the elevation of these tracts, and 
consequent denudation, in a period preceding the Carboniferous. 
The comparative depression of the intermediate area of South 
Westmoreland, and probably Lancashire, and of South Wales pre- 
served these beds or a portion of them, or even led to further 
deposition, so that 10,000 feet of red beds are found in Hereford- 
shire which are missing in Denbighshire. While in the areas of 
elevation the unconformity at the base of the Carboniferous is 
immense, in the areas of depression the gap 1s apparently filled up 
through the comparatively slight denudation to which the beds were 
exposed. 
Neglecting minor undulations, the general tendency of the Wenlock 
shale of North Wales is to dip in a north-east direction off the Bala 
beds of Conway and Bala. If this dip is continued under the Car- 
boniferous strata it must bring on in natural succession the missing 
Silurian beds in the direction of Liverpool and Lancashire. On the 
southern side of the Lake-district, where the Silurians reemerge, the 
series is actually complete as far as the Kendal Flags (Tilestones) 
before it is overlapped by the Carboniferous. 
It is therefore probable that in the old synclinal between Wales 
and the Lake-district, Silurian beds higher than any existing in 
North Wales underlie the Carboniferous strata. The resemblance of 
the Ffernant pebbles to the Westmoreland beds has been remarked 
by Mr. Etheridge; but from the large size, incomplete rounding, 
and friable nature of some of the pebbles, it is not probable that 
they have travelled so far as from the Lake-district to Wales. We 
therefore suggest the probable extension of the Ludlow beds under 
Lancashire as the most likely source from which they can have been 
derived. 
Mr. Goodchild has been kind enough to furnish us with the 
following notes on conglomerates occupying a similar position on 
the borders of the Lake-district. They rest with an extreme uncon- 
formity upon all the older rocks. On the other hand, they pass up 
into the limestone, or are sometimes rather sharply divided from it. 
They are also interstratified with beds of sandstone and even shale, 
which occasionally form the mass of the deposit. There is evidence 
in the conglomerates of their having been drifted from a north-west 
direction. 
In the Isle of Man, near Castletown, the conglomerate rests on 
the smashed edges of nearly vertical Silurian strata. It is inter- 
stratified with discontinuous beds of sandstone and grit. In the 
upper part it is interbedded with Carboniferous Limestone. The 
Peel Sandstones are described by Mr. Horne* as containing occa- 
sional bands of breccia and thin cornstones, and as passing con- 
formably under the limestone. In all cases the conglomerates are 
highly charged with iron. 
Over a large area in the north and west of England and Wales 
these red conglomerate sandstones and shales are conformable to 
the Carboniferous Limestone, and occasionally interstratified with 
* Trans, Edinburgh Geol, Soc, 1874. 
