612 GEOLOGY OP THE WARWICKSHIEE COALFIELD. [DeC. I912. 



and at Ximeaton, where the junction between the Trias and 

 the older rocks is an unconformitj^ and the fault is entirely in 

 Trias, the displacement is probably quite small. On the upthrow 

 side of the fault the Cambrian has been proved beneath the Lower 

 Keuper at The White Stone, Burton Hastings (13), and at 

 Nuneaton (14). On the downthrow side a boring at Lindley (16) 

 has penetrated more than 600 feet of Keuper without reaching 

 the base of the subdivision, Near Market Bosworth, 7 miles 

 north-east of Nuneaton, a series of borings passed through the 

 Trias into the Cambrian ; and Mr. Horace Brown (89) has shown 

 that this part of the Palgeozoic floor forms a sub-Triassic anticline 

 parallel with the Nuneaton ridge. 



The western and north-western boundary-fault is probably the 

 most important one ; but at present there is no means of estimating 

 the displacement, as the thickness of the strata is unknown. On 

 this point the only evidence available is the King's-Heath Boring, 

 near Birmingham, which ended in Keuper rocks at a depth of 

 1106 feet ; also a boring farther north at Streetly, which proved 

 about 1850 feet of red ' Permian ' sandstones, marls, and con- 

 glomerates of unknown age beneath 50 feet of Bunter Pebble- 

 Beds. South of the district, at Stratford-on-Avon, the base of the 

 Keuper has not been reached at a depth of 800 feet. Nothing 

 Tery definite can thus be affirmed concerning the southern portion 

 of the county. 



With regard to the age of the movements which have affected 

 the coalfield, it is obvious that the main folding and faulting took 

 place after the deposition of the Upper Coal Measures and before 

 the Trias was laid down ; but, v/hether it is of pre- or of post-Permian 

 age is not so clear. The Permian has been proved unconformable 

 to the Keele Beds, and so it is probable that the main folding was 

 pre- Permian; but there has been subsequent upward movement 

 of the old Palaeozoic ridges along the same lines in post- Permian 

 and also in post-Triassic times. 



(E) Conclusion. 



The Coal Measures of Warwickshire are merely the remnants 

 of an extensive sheet which formerly overspread a wide area in 

 the Midlands. With other existing portions of this sheet it is 

 possible to institute a close comparison. In other words, the 

 stratigraphical succession, lithological characters, and fossil con- 

 tents of the Coal Measures of Warwickshire can be correlated with 

 those of the other coalfields of the Midland counties, and more 

 especially does this apply to the South Staffordshire Coalfield. 

 Such a correlation is indicated in the appended table (p. 613). 



In this connexion, it may be remarked that it is stiU a matter 

 for speculation whether Upper Coal Maasures were ever deposited 

 over the Leicestershire area ; but this does not affect the question 

 of the correlation of the Middle Coal Measures. The Middle Coal 



