XC PROCEEDINGS OE THE GEOLOGICAL SOCIETY. [May I906,. 



Again, the nature of the dome is in itself suggestive. As I have 

 elsewhere remarked, 



' regular dome-shaped uplifts, having a symmetry like that possessed by the 

 Lake-District dome, are produced, as far as we know with certainty, in one 

 way only, by intrusion of a lenticular mass of igneous matter beneath, forming 

 a laccolite. Subsequent to the deposition of tbe New Red Sandstone of Britain, 

 we have no evidence of intrusion of igneous rock until early Tertiary times, 

 when the intrusions of plutonic rock occurred in Skye, Rum, Ardnamurchan,. 

 Mull, and Arran, in a line which, if continued southwards, would 

 pass beneath the Lake District.' 1 



I quote this remark here, as in some degree corroborative evidence 

 in favour of the suggestion of the Tertiary date of the uplift. To 

 the nature of the dome I shall have occasion to refer more fully 

 presently. 



The actual age of the uplift is only important in a subsidiary- 

 degree to the subject under consideration. My main object is to 

 show the effect on the present physical structure of two important 

 sets of movements, of which one occurred in Devonian times and 

 the other later, almost certainly after the deposition of the New- Red- 

 Sandstone rocks, possibly (I think, probably) in Tertiary times. 



Let us now pass to a consideration of the characters of the dome- 

 shaped uplift and the effects of accompanying movements, in 

 illustration of which a sketch-map is appended (fig. 4, p. xci). 



The high ground of the North of England is determined mainly 

 by the Pennine anticline and by the Lake-District dome; and I 

 have argued that the final and, so far as we are concerned, im- 

 portant differential movements which affected the topography of the 

 north were geologically contemporaneous. 



The general axis of the Pennine Chain was north and south, and, 

 with such an axis and a symmetrical dome on the west, we should 

 find either a circumference of New-Ped-Sandstone rocks running 

 round the dome ; or, if the dome on the east touched the Pennine 

 uplift, the newer rocks would be there absent, and the Carboniferous 

 rocks of the margin of the dome would be continuous with those 

 of the Pennine Chain. 



There is a tract on the' east, marked by the absence of New- 

 Red-Sandstone rocks (which elsewhere surround the dome), 

 extending from Kirkby Stephen on the north to the neighbourhood 



'The Waterways of English Lakeland' Geogr. Journ. vol. vii (1896) p. 604.. 



