A. Sirahaii's Address to Section C, Geology. 455 



therefore, presents a history corresponcling in its main events with 

 that of the Lake District. It had nndeif^one 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 hare. 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 rt'gions pre-Carboniferous movements had been 

 extremely active. For example, an axis of compression and upheaval 

 ranges from north-east to south-west, 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 particular 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. Eecent work by 

 Mr. W^. Gibson has shown that the vertical displacement of the 

 Coal-measures amounts to no less 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 Eadnorshire, and thence into Brecknock. 



The second is the Apedale Fault of the North Staffordshire 

 Coalfield. In working 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 

 Gverthrust 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 Ked 

 Sandstone has been pushed from that direction against and even 

 over Coal-measures, while the strata have been forced up into 



