240 TRANSACTIONS OF THE [maR. 15, 



of the Trias is proved by the latter lying upon the Lower Car- 

 boniferous along the southern extremity of the Derbyshire hills 

 (op. cit., p. 329) but that it was post-Permian, as is supposed by 

 Professor Hull, rests upon the belief that a gi'eat anticlinal fault 

 traversing Lancashire and contemporaneous in its development 

 with the upheaval of the Pennine chain is older than a second 

 fault which it meets to the south in Staffordshire. The anti- 

 clinal fault fractures the coal measures and passes under the 

 Trias in Staffordshire without fracturing them, but the second 

 fault which it joins fractures both. 



Immediately to the south of the Lancashire coal field the anti- 

 clinal fault is accompanied by a parallel series, one of which, 

 known as the " Red Rock Fault," throws in the Permian sand- 

 stone against the Carboniferous. 



If the anticlinal fault and the parallel system mentioned are 

 of the same age as seems most probable, it follows that the 

 former, as well as the latter, is of post-Permian age and, since the 

 anticlinal fault is directly connected with the upheaval of the 

 Pennine chain, the age of the latter appears to be established as 

 post-Permian and pre-Triassic. 



It would thus appear that the dominant features of the topog- 

 raphy of Lancashire were determined by two systems of folds 

 and the denudation of their crests before the commencement of 

 the Mesozoic. 



Faulting. 



3. The third change which was induced in the Lancashire Coal 

 Measures was caused by the great system of faults which strike 

 across the coal field from N. N. W. to S. S. E. That these are 

 post-Triassic is shown by their continuance into the Trias of the 

 Cheshire plain. That they are possibly post- Jurassic is assumed, 

 because the continuity of deposition was not interfered with 

 from the top of the Trias to the close of the Jurassic so far as 

 is known. 



The more important of these faults will be dealt with under 

 their respective districts. 



Oldham District. 



Several faults start in the neighborhood of Ashton-under-Lyne 

 and range northwest as far as Rochdale and He}' wood, with 

 downthrows of from 100 to 200 yards. 



Immediately to the east of this district in the Millstone Grit 

 countr}' runs the great Pennine fault, passing almost north and 

 south and bringing up the Yoredale shales against the Mill- 

 stone Grits. 



