intra-Jurassic Movements. 20*7 



movement along the older Charnian axes.' If this were so it would 

 explain why more than one of the Jurassic anticlines connects 

 with the present visible Warwickshire Coalfield. 



If now we are justified in our conclusions that each of these 

 slight uplifts in the Mesozoic rocks of the Midlands indicates the 

 line of a deeper-seated and more powerful uplift in the underlying 

 Palaeozoic rocks, the importance of their further study is obvious, 

 and it is seen that detailed zoning and detailed records of thickness 

 may prove of import for the tracing of the larger underground 

 structures. Any facts which may shed light on the underground 

 structure of this region are doubly valuable because of the 

 possibility of the existence of concealed coalfields. Taken in con- 

 junction with the gradually accumulating evidence as to the deptli 

 of the Palaeozoic floor," the Mesozoic folds may yet serve as guides 

 to the most likely areas for finding productive coal-measures at 

 reasonable de|)ths. 



V. General Consideration of the Underground Structure 

 OF the Southern Midlands. 



Surveying the underground structure of the country as a whole, 

 attention may be called to a peculiar symmetry in the general 

 deposition of the Palaeozoic rocks. In the centre of England we 

 have the Pennine axis which fingers out southwards into a number 

 of subordinate folds in Carboniferous rocks. They are flanked to the 

 south-east by a large area of older rocks, Devonian and Silurian 

 with some Cambrian and pre-Cambrian, which underlies, so far 

 as we know at present, most of the district between Northampton- 

 shire, Buckinghamshire, Herefordshire, and East Anglia.^ This 

 mass of older rocks occupies much the same position on the south- 

 east side of the Pennine axis as the mass of Devonian, Silurian, and 

 older rocks in Wales, on its south-west side. Not only so, but just 

 as the Welsh rocks have a predominant south-westerly strike which 

 gradually swings to east and west in South Wales, so the East Anglian 

 mass, judging from present information, is affected by south-easterly 

 structures Avhich probably swing round to east-west under the 

 region of the Thames estuary. The Kent Coalfield, with its highly 

 inclined Carboniferous rocks, may thus compare structurally with 

 the Pembrokeshire Coalfield, with its highly compressed structures. 

 In each case the compression of the Carboniferous rocks may be 

 accounted for by proximity to an area in which the Lower Palaeozoic 

 rocks strike east and west. 



' Compare Matley, op. supra cit. ; also A. Morley Davies & J. Pringle, 

 " Two Deep Borings at Calvert . . ." : Quart. Journ. Geol. Soc, vol. Ixix, 

 1913, p. 33.5 ; also Balcer, " Charnian Movement in East Kent " • Geoi.. Mac, 

 Dec. VI, Vol. IV, 1917, p. 398. 



- Stralian, Presidential Address : Quart. Journ. Geol. Soc, vol. Ixix, 1913, 

 p. Ixx. See also A. Morley Davies & J. Pringle, ibid., p. 334. 



' Strahan, op. cit. 



