352 ME. J. E. MAKE ON LIMESTONE-KNOLLS IN [Aug. 1 899, 



quarry. It seems highly improbable that the coal is truly inter- 

 stratified with the marine limestones, and I consider that the most 

 probable explanation of its occurrence is that the limestone has 

 been thrust over the Coal Measures beneath, and that the coal has 

 been squeezed up between two bedding-planes of the limestone. 



South of the coaly band is a great belt of breccia w^hich 

 seemed to me to give indisputable proof of its formation by earth- 

 movements. The beds in its vicinity are much marked by slicken- 

 sides on their surfaces. — April '26th, 1899.'] 



The Clapham Yalley I have not recently seen ; so far as I 

 remember, the scar runs some distance up the valley. This is 

 certainly the case at Austwick, where the fault is mapped in a blunt 

 T, of which the apex points up the beck, the apex being more than 

 ^ mile north of the direct line of the fault on either side of the 

 valley. 



The crossing of the Ribble at Settle requires further consideration. 

 On the Geological Survey map, the apex of the V points down the 

 valley, in which case the hade of the fault would be normal. Exami- 

 nation of the area shows that the continuous scar which, I believe, 

 marks the boundary of the fault, runs far north of this along the 

 Settle and Beacon Scars (Attermire Scars), and so to the Kibble 

 between Settle and LangclifFe, and on the west side of the valley runs 

 at the back of the hill above Giggleswick, thus cropping out with a 

 V-shaped outcrop, of which the apex points up the valley. South 

 of this line, much limestone occurs on the hill immediately behind 

 Giggleswick, in the Eibble, and on the hills between the Attermire 

 Scars and their continuation, and the southern bank of the Stockdale 

 Valley, but this limestone possesses knoll-structure, and has yielded 

 fossils which are practically identical with those of the Cracoe 

 knolls. At Malham the same occurrence is observed, the scar 

 sweeping up the valleys of Malham Cove and Gordale, while on the 

 south is limestone showing knoll-structure. The Middle Craven 

 Pault, in fact, appears to be a thrust-plane, inclined downward 

 towards the north, and, judging from the Austwick outcrop, the hade 

 of the fault makes but a small angle with the horizon. 



In support of this view, I may point to the nature of the throw. 

 All the way from Ingleton to Gordale the Scar Limestone occurs 

 on the north side of the fault. On the south side Permian beds 

 occur west of Ingleton, Coal Measures at Ingleton, different members 

 of the Millstone Grit from here to beyond Settle, Lower Carboni- 

 ferous rocks west of Settle, Millstone Grit again east of this, and 

 Lower Carboniferous rocks once more in the Malham Valley. 

 This disposition can be partly, but not altogether, explained east of 

 Settle by differences in the level of the fault- outcrop ; but this will 

 not account for the actual occurrences along the rest of the line 

 where the country is fairly level. The beds on the south side are, 

 in fact, thrown into a series of folds, these folds are abruptly cut 

 off by the faults, and do not recur on the north side, where 

 the beds are almost horizontal at a little distance from the fault. 

 As the folds to the south are cut off abruptly by the fault, they 



