Vol. 67.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxXXl 



or in the Warwickshire Coalfield have been influenced by older 

 directions. In the same way the Charnian direction of movement 

 makes itself felt not only in the Cambrian rocks of Nuneaton, but 

 also in the later Carboniferous rocks. Similarly, the Armorican 

 direction has made itself felt in the Wealden Arch and in the 

 London Basin. 



The directions of movement are convincingly betrayed by the 

 first infillings of terrestrial and lacustrine sediments which follow 

 closely upon the movement. Very significant in this respect is the 

 position of the main Torridonian outcrop. Still more definite is 

 the evidence of the lines that border the Old Red Sandstone areas, 

 of which enough is preserved, as shown by Sir Archibald Geikie, 

 to give a fair idea of the position and outline of the lakes of this 

 period. Almost equally striking is the run of the outcrops of 

 the Permian and Triassic Systems, flanking the Pennine, running 

 down to the Bristol Channel, and forming a tongue along the main 

 syncline of North Devon. 



The infillings of the New Red Sandstones, followed by the rest 

 of the Mesozoic deposits, are particularly instructive. We find that 

 they occur in three types of localities : — 



(i) Planking the features produced by the immediately preceding 

 movements, and best preserved on the east side of them. Also in 

 the minor synclines of those movements. 



(ii) In the ' lee ' area which often occurs between the rocks 

 affected by the immediately preceding movement and the firm land 

 of an earlier movement. The New Red Sandstones flanking the 

 west of the Pennine and extending into the Irish Sea exemplify 

 this position. 



(iii) In the rejuvenated folds of still older rocks — for instance, in 

 the vales of Eden, Dee, and Clwyd, in the rift-valley off Western 

 Scotland, and in the Irish loughs such as Carlingford, Belfast, 

 Larne, and Poyle. 



The areas of deposition in our own islands thus tended to become 

 increasingly complex as one movement succeeded another. 



The study of the chief British movements makes it clear that in 

 that region, at any rate, the distinction between orogenic and epeiro- 

 genic movement is a question rather of degree than of kind. The 

 so-called ' orogenic ' movements have been accompanied by sharper 

 folding and faulting and the production of marked relief; the epeiro- 

 genic by the uplift of broad anticlinal curves, and by denudation 

 over large areas of comparatively small thicknesses of sediment, and 

 that for the most recently deposited. Among the typical orogenic 



