536 REPORT—1904. 
where it reaches the Triassic margin, proves that it is in part at least of pre-Triassic 
age. In Anglesey also there has been strong post-Carboniferous folding in the 
same N.E.-S.W. direction. 
It is to be noticed, further, that the Carboniferous rocks maintain their 
characters to their margins on the flanks of the Clwydian Hills and other ranges 
of Silurian rocks in North Wales. Both along the coast, and even in a little 
outlier preserved near Corwen by an accident of faulting, they show a persistence 
of type and of detail in sequence which could hardly have been maintained had 
the Silurian uplands existed in Carboniferous times. Theinference that the uplands 
of Denbighshire and Flintshire are the result of post-Carboniferous upheaval is 
strengthened by the fact that the Carboniferous rocks reposing on their flanks are 
tilted at an angle which would carry them over their tops. This part of North 
Wales, therefore, presents a history corresponding in its main events with that of 
the Lake District. It had undergone elevation and denudation in pre-Carboniferous 
times on a scale so vast that rocks showing slaty cleavage and other indications 
of deep-seated metamorphism had been laid bare. But in both cases it was in 
consequence of the post-Carboniferous movements that the leading physical features 
as they exist to-day began to take shape. 
In both these regions pre-Carboniferous movements had been extremely active. 
For example, an axis of compression and upheaval ranges from N.E. to §.W., 
involving the Lake District, the Isle of Man, and Anglesey. It belongs to the 
Caledonian system of disturbances which is developed on a large scale further 
north, and which sufficed here to cause slaty cleavage and presumably the 
extrusion of the Shap granite. I mention this pre-Carboniferous axis to point out 
that it offers an explanation of the direction taken by the post-Carboniferous 
disturbances of Whitehaven, Pendle, Anglesey, and possibly Bala. With the 
exception of the last-named they lie well within the region affected, and alone 
among the post-Carboniferous axes take that particular direction. 
The Pennine axis ends as a physical feature in South Derbyshire and North 
Staffordshire on the margin of a deep channel filled with Triassic marl, which 
extends westwards from Nottingham into Shropshire. In this part of England 
there springs into existence a remarkable series of disturbances tending to radiate 
southwards. The westernmost of these is the great fault which forms the 
western boundary of the North Staffordshire Coalfield. Recent work by Mr. W. 
Gibson has shown that the vertical displacement of the Coal Measures amounts to 
no Jess than 900 yards, but that it is far less, though recognisable, in the Trias, 
proving that the disturbance was in the main pre-Triassic. The fault ranges from 
Macclesfield in a south-south-westerly direction, is lost to view under the Trias 
near Market Drayton, but is recognisable further on in the great dislocation which 
passes along the western side of the Wrekin, and thence through Central Shropshire 
by Church Stretton to Presteign in Radnorshire, and thence into Brecknock. 
The second is the Apedale Fault of the North Staffordshire Coalfield. In work- 
ing the coal this disturbance has been found to possess the structure of a broken 
monocline, a fold with fracture such as may be regarded as an early stage in the 
formation of an overthrust from the east. It runs through the coalfield in a 
direction slightly east of south, and then passing under the Trias of Stafford ranges 
for Wolverhampton and Stourbridge. This fault is mainly pre-Triassic, but 
what Mr. Gibson believes to be a continuation of it, following the same direction 
as far south as Hanbury, certainly effects a great movement in the Trias. 
The third disturbance runs on the east of the Forest of Wyre Coalfield in a 
direction a little west of south. Here, as I learn from Mr. T. C. Cantrill, the thrust 
from the east is obvious, for Old Red Sandstone has been pushed from that direction 
against and even over Coal Measures, while the strata have been forced up into a 
vertical position for some miles. In South Staffordshire all the Carboniferous 
rocks, including the ‘Salopian Permian,’ are involved in this and the previously 
Span: movement, proving that both disturbances were of post-Carboniferous 
ate. 
Traced southwards, this disturbed belt leads to Abberley, and there connects 
itself with the well-known Malvernian axis, The broken belt known by that 
