SKIDDAW SLATES. 



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Many years ago Daniel Sharpe noticed 

 that the slate was apparently hardened 

 by proximity to the granite in quarries 

 at Thornthwaite Gill in Ralphland, and 

 on Rosgill Moor. There, however, ap- 

 pears to be no connection between the 

 cleavage and metamorphism.' 



The peculiar ' cone-in-cone ' structure is often 

 met with in these rocks. Ores of Iron, Copper, 

 Cobalt, and Lead occur in places. The quartz- 

 veins of Carrock-fell, north of Keswick, are noted 

 for rare minerals.'- Slate-pencils have been largely 

 manufactured near Shap. Mr. Sharpe observed 

 that slate-pencils were cut from a slate which is 

 soft enough not to scratch, and which can be split 

 down the planes of secondary cleavage with nearly 

 the same facility as along the true cleavage. The 

 latter character is not common. Slate-pencils are 

 made at Knock Fell, Ashlake Pike, etc. There 

 are two quarries near the village of Shap. The 

 slate seldom forms good workable material for 

 roofing, as it splits up into small flaky pieces or 

 pencil-like fragments. It is generally of very 

 uniform texture, soft, fine-grained, and very 

 fissile, and has been occasionally employed in 

 the vicinity of Keswick and Hesket Newmarket 

 for roofing houses ; but for this use it is not very 

 suitable, as it easily perishes in the atmosphere. 

 The best slate has been procured at Bowscale 

 Fell. In consequence of its want of durability, 

 the mountains ot this slate, as John Phillips re- 

 marked, have smoother contours, more uniform 

 slopes, and a more verdant surface than those of 

 the Borrowdale series (Green Slates and Porphy- 

 ries). Hence the smooth slopes of Skiddaw and 

 the rude crags of Scafell. 



BORROWDALE SERIES. 



In Cumberland and Westmoreland, 

 mainly overlying the Skiddaw Slates, 

 comes a great thickness of volcanic rocks, 

 termed the Green Slates and Porphyries 

 by Otley and Sedgwick, and the Volcanic 

 Series of Borrowdale by Prof. Harkness 

 and Dr. Nicholson (1872). The latter 

 term, derived from Borrowdale, where the 



1 Q. J. v. 115, 12S. See also Bonney, Address 

 to Geol. Soc. 1886. p. 87. 

 ^ Harkness, Q. J. xix. 124. 



