Yol. 62.] ANNIVERSARY ADDRESS OF THE PRESIDENT. IxXXV 



appears to be no evidence pointing to the formation of the dome in 

 Triassic times. Indeed, the probability' is that the whole of the 

 North of England was covered with Triassic rocks at the end of that 

 time. The similarity between the Triassic rocks on the two sides 

 of the Pennine Chain is sufficient to indicate that they were formed 

 under very similar conditions and in one physiographical region. I 

 shall eventually argue that important movement took place along 

 the Pennine Fault in post-Triassic times, sufficient to elevate the 

 Pennine Carboniferous rocks into a ridge, of which the present 

 chain is the relic. If this ridge were depressed to the level 

 which it occupied before the later faulting, a comparatively-level 

 tract would be produced, over which the Triassic rocks might well 

 have extended. 



II. Production oe the Dome. 



In discussing the changes which occurred in and around our area 

 during the deposition of the Jurassic, Cretaceous, and Eocene rocks 

 of Britain, it is necessary to pay regard to some of the features 

 presented by areas somewhat remote from that which we are 

 specially considering. 



Leaving out of account the east-and-west strike of the 

 Mesozoic rocks of East Yorkshire, the rocks of this date east of the 

 Pennine Chain have a north-and-south strike with an easterly dip, 

 the strike being parallel with that of the axis of the Pennine Chain 

 itself. They have been described by Prof. "W. M. Davis as giving 

 rise to a coastal plain abutting against the Pennine Chain. But I 

 can find no evidence of the existence of this chain when they were 

 deposited. If it existed, the dip should be due, not to earth- 

 movement, but to deposition along a sloping shore falling eastward ; 

 in which case the deposits should show distinct indications of an 

 approach to land when traced westward. Surely, for instance, the 

 Chalk would have some of the detrital matter derived from the 

 Pennine Chain. But, even if this were not the case, the evidence is 

 all in favour of the dip of these rocks being due to subsequent move- 

 ment, and not to deposition on a sea-floor sloping eastward. Now, 

 the junction between the Trias and the Lias near Middlesborough 

 is about 40 miles distant from the watershed of the Pennine Chain 

 immediately to its west. If we suppose that the dip of the plane 

 separating the Lias from the Trias is only 1°, and restore the old 

 surface to the west, assuming that the dip still remains at 1°, this 

 would carry the position of the plane above the watershed of the 

 Pennines to a vertical height of nearly a mile above sea-level. 



