^'^^' 55-J ^^^ CEATEX DISTKICT OF TOEKSHIRE. 351 



in possession of a much larger mass of evidence concerning the distri- 

 bution of Lower Carboniferous fossils than that which is now at 

 our disposal. 



If the foregoing correlations conld be proved correct, and my views 

 of the structure of the district south of the fault were established, 

 the deposits which now occur on opposite sides of the fault may 

 have been continuous, and generally similar in thickness, lithological 

 conditions, and fossil contents : and the present differences would be 

 due, as regards thickness, to repetition of strata on the south side, 

 and, as regards lithological characters and fossil contents, to changes 

 in the characters of the rocks produced by orogenic movements 

 acting subsequently to the deposition of the strata. 



Til. Nature of the Movemej^ts which have affected the 

 Rocks south of the Craven Faults. 



Owing to the general north-and-south trend of the main axis of 

 the Pennine Chain, and the east-and-west trend of an anticline 

 running from Morecambe Eay to the Dales district of Yorkshire, 

 the coalfields of the JSTorth of England have a cruciform arrange- 

 ment, the Cumberland and South Lancashire coalfields lying on the 

 west of the Pennine axis, and the Northumberland-Durham and 

 Yorks-jSTotts -Derbyshire coalfields on the east, while the Cumbrian 

 and jN'orthumberland-Durham fields lie north of the east-and-west 

 anticline, and the other two south of it. It is true that the 

 symmetry of this structure is partly destroyed by the existence of 

 the Lake District dome, which, as I hope to show elsewhere, is of 

 much later origin than the structures that we are considering. 



The Craven system of faults seems to be clearly connected with 

 this east-and-west anticline, and certainly with complications of it, 

 causing the rocks on the south to be thrown into minor folds, 

 which have axes running in a general north-easterly and south- 

 westerly direction. As the Craven Faults also separate the two 

 types of area considered in the foregoing pages, it is necessary to 

 devote some attention to the character of those faults. 



Are the Craven Faults thrust-faults? The cessation 

 of knoll-structure to the north is determined by the Middle Craven 

 Fault, by far the most important of the system, and it is necessary 

 to examine the trend of this fault in order to arrive at a conclusion 

 as to its nature. First, we may consider its outcrop at the surface. 



In its course from near Ingleton to beyond Gordale, it crosses 

 important valleys at Ingleton, Clapham, Austwick, Settle, and 

 Malham. At Ingleton, the phenomena displayed by the rocks in 

 the large quarry on the west side of Dale Beck are certainly sug- 

 gestive of thrusting over the Coal Measures. 



[In connexion with this matter, the occurrence of a deposit of 

 crushed coal, apparently inttrstratified with the limestones, in the 

 great quarry by the side of Dale Beck, deserves notice. This coal 

 thins out and disappears, when traced upward along the face of the 



