1865,] HAEKNESS — CTJMBERLAND AND WESTMORELAND. 245 



nearly in contact with the Keisley limestones which form the 

 northern slope of this hill. On the south-east side of Whinskill 

 there are several quarries which have been wrought for dyking- 

 purposes, and in these we have good exposures of the rocks which 

 occur to the south-east of the Keisley limestone. 



Here the strata consist of hard, dark-coloured, flaggy slates with 

 a highly inclined N.N.W. dip. They have also a vertical cleavage, 

 and in every respect they resemble the coarse Skiddaw slates 

 which underlie the softer shaly beds of the higher portion of this 

 series. 



The altogether discordant dip, and the mode in which the Skid- 

 daw slates of Whinskill come in contact with the Coniston limestone 

 of Keisley, indicate the existence here of a great fault, which brings 

 the Lower Skiddaw, or a lower portion of the Lower Llandeilo, into 

 contact with the Coniston or Bala limestone. The amount of the 

 throw- down to the N.N.W., produced by this fault, cannot be ex- 

 actly determined, since there is as yet no means of knowing the 

 exact position of the portion of the Skiddaw slate in contact with the 

 Coniston limestone, or the total thickness of the porphyries, green 

 slates, ashes, and fossiliferous flaggy shales which intervene be- 

 tween the top of the Skiddaw slates and the base of the Coniston 

 limestone. There are, however, good grounds for assuming that 

 the amount of throw exceeds 10,000 feet, which is probably the 

 thickness of the interposed rocks separating the Skiddaw slates 

 from the Coniston limestone. This fault is of an ancient date, 

 as it in no way afifeets the Upper Old Eed Sandstone and the Car- 

 boniferous strata which overlie the Older Palaeozoic rocks. 



Whinskill forms the north-west boundaiy of a deep hollow called 

 Highcup Gill, which, after traversing the Lower Silurian rocks, 

 penetrates the Old Red Sandstone and Carboniferous group. This 

 hollow is drained by a stream called Highcupgill Beck *. On the 

 south-east side of this hollow, at Harbour Flat, the flaggy Skiddaw 

 slates are also seen, having been worked at a quarry here. They 

 dip N.N.W. at 60°, and they are intersected by the coarse vertical 

 cleavage before alluded to. The same rocks form the west slope of 

 the hill called Middle Tongue, where they are capped by an escarp- 

 ment of the newer Palaeozoic rocks. The hard flaggy Skiddaw 

 slates occur on the north side of Murton Pike (1949 feet), and are 

 here much intersected by quartz-veins. They are still better seen 

 on the western side of this hiU ; and at the base of the southern 

 slope they are well exposed in a cliff called Thornarbour Scar. 

 These Skiddaw-slate rocks form the whole of Murton Pike, except 

 the eastern side, where they are overlain by the newer Palaeozoic 

 strata. Wherever the flaggy slates are seen in Mujton Pike they 

 have a N.N. W. dip and vertical cleavage ; and they retain through- 

 out the same type of mineral character. 



Immediately south-east of Murton Pike, the same rocks are seen 

 in Murton Beck. They occupy the slope between Murton Beck 



* In this glen one of the finest sections of the Carboniferous Rocks (inckiding 

 the Whinskill) of the Pennine escarpment occurs. 



