of the Cumbrian Mountains. 61 



of Bawfell and Wildboar Fell, to the ridg-e between Mollerstang and Raven- 

 stone dale ; and that along the whole of this line there are enormous and most 

 complex dislocations. Some of these phenomena I hope to describe more at 

 length in a future communication ; and for the present I only observe, that a 

 great upheaving force acting at once upon the two contiguous and uncon- 

 formable systems, produced a great strain and separation of parts, accompanied 

 with fractures and dislocations, principally along the line of their junction*. 



In a part of the range between Mollerstang and Ravenstonedale the cluster 

 of the older mountains, by deflecting to the north-west, quits the central car- 

 boniferous chain ; and it becomes a question of some consequence to deter- 

 mine the further range and nature of the great Craven fault. The ruptures 

 produced by it are fortunately on a scale too great to be overlooked or mis- 

 understood. It ranges through Mollerstang into the hills immediately south- 

 east of Kirkby Stephen, and thence skirting the escarpments which trend 

 towards Stainmoor, finally stops near the foot of the mountain-pass. Its pro- 

 gress is marked by a lofty ridge of carboniferous limestone, which has been 

 upheaved from the very base of the whole system, contorted and shattered, 

 and then sent headlong into the valley, where it is to be seen on edge for 

 many miles ; and where its lower extremities lie buried under accumulations of 

 alluvial matter and the horizontal conglomerates of the new red sandstone f. 



In following these dislocated ridges in the opposite direction, we may trace 

 them into the calcareous hills of Ravenstone dale, where they expand them- 

 selves and assume a more horizontal position, and in this way gradually pass 

 into the unbroken calcareous zone which skirts the north side of the Cum- 

 brian mountains as far as Egremont. Thus, it appears that the northern and 

 southern calcareous zones of the Cumbrian mountains are cut off from the 

 central chain by the same fault, which, both in the neighbourhood of Ingle- 

 ton and Kirkby Stephen, has produced a great downcast on the western side 

 of its range;};. 



So far it appears that we have a clear and consistent explanation of the re- 



• See PI. V. figs. 4. 5. 



t See the southern extremity of the section, PI. V. fig. 7. 



% See PI, V. figs. 3. 7. The effects produced along the line of dislocation on the lower 

 beds of the carboniferous system vary with the circumstances of the case. Where the beds abut 

 against the steep sides of the greywacke chain, their broken ends have undergone a movement 

 of elevation. Under such circumstances a depression like that at Ingleton, or the still more com- 

 plex derangement of the strata, like that in the valley above Kirkby Stephen, was obviously im- 

 possible. See PI. V. figs. 4. 5. These two figures are ideal ; the former being intended to repre- 

 sent the undisturbed, and the latter the disturbed, position of the greywacke and carboniferous 

 series. 



