Kendall: The Concealed Coalfields of YorksJiire, etc. 199 



A study of the country bounding the York, Derby, and 

 Nottingham Coalfield reveals three great posthumous folds, all 

 of which (whatever their previous history) moved powerfully 

 and with decisive effect, after the deposition of the Coal 

 Measures and before the Permian rocks were laid down. 



As the arches rose the crests were worn off and the Permian 

 rocks were deposited on the eroded plane, sometimes' thinning 

 off against the flanks of the ridge, as was the case with the 

 Pennine arch and the Charnian fold, in other cases extending 

 quite across the eroded arch as in the case of the very complex 

 and disturbed region between the Yorkshire Coalfield and that 

 of Durham. 



The Boundaries of the Coalfield. 



The boundaries which I have drawn on the map accompany- 

 ing this report are traced in each instance in relation to some 

 considerable anticlinal fold — those on the north and the south- 

 west are so patent and the Coal Measure so clearly extend up 

 to their margins so far as they can be followed, that I feel 

 a considerable degree of confidence in their validity. On the 

 east the evidence is not nearly so complete, but I have drawn 

 the line at the first anticlinal fold, indeed the only one between 

 the coalfield and the sea, and have found corroboration in 

 evidence of an entirely different character. The most doubtful 

 boundary is that on the south-east. 



The prolongation of the south-western boundary is so clearly 

 marked right down to the belt of Cretaceous rocks near 

 Cambridge that only a desire to err a little on the side of under- 

 estimation induces me to draw a boundary short of the point 

 where the Charnian fold would become merged in the great 

 plateau of ancient rocks which underlies the London Basin. 

 I have studied with the utmost care the structure of the country 

 from Nottingham to Cambridge in search of any indications of 

 an anticlinal fold or any considerable disturbance which might 

 mark a limit to the coalfield in that direction, but without 

 success. . 



iV small and very low anticline runs at right angles to the 

 Charnian axis in Buckinghamshire, but it cannot be traced into 

 the Fen countr}' with any degree of confidence, and even if it 

 could it is upon so small a scale that it might well be doubted 

 if it marked an actual interruption to the extension of a coai- 

 basin, rather than a minor roll in the strata similar to that 



1905 July I. 



