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with any experienced geologists. The only rock that I have encountered since I 

 received your letter is that of Castlehead, near this town. I find the most general 

 bearing of joints in that rock is about 46° W. of true N., and nearly perpendicular ; 

 at least in the upper part : but there is a portion of rock appearing on the S.E. 

 side, about three yards thick, which is divided by parallel joints bearing 40° E. of 

 true N., and dipping to the N.W., at an angle with the Horizon of forty degrees. 

 Beneath this the rock appears to regain its former perpendicularity. In a quarry 

 on the E. side, where they are getting stones for a new church, now building at 

 the south end of Keswick, I observed a master- joint bearing about 65" W., and on 

 the S. W. side I observed one in the magnetic meridian : but there are indeed joints 

 in every imaginable direction. 



I had a letter from Professor Phillips, in which he asks if I have noticed any 

 general directions to the joints, etc., in the slate ; I answered that I had not ; and 

 to his question — ''is there any 'bate' besides the cleavage?"— I answered that, 

 according to my notion, the Skiddaw Slates have a cleavage without a bate: the 

 green slates have a bate synonymous with cleavage ; and that the Ingleton slates 

 possess both bate and cleavage in some degrees. 



I dare say you are acquainted with that property in the green slates, especially 

 those of Borrowdale, which admits of their being cut, that is, being divided into 

 breadths in a certain direction ; of which I cannot discover the relation to either 

 the cleavage or stratification. This, and the bate, I am willing to refer to 

 crystalline action ; but that of the joints I cannot comprehend ; as they include 

 angles of such various degrees. 



I showed your letter to my neighbour Wright, who has of late had better and 

 more frequent opportunities of observing and learning the opinions of others than 

 I have had; but he has not paid attention to this part of the subject. 



I have been puzzled a good deal by what you call a false stripe in the Skiddaw 

 Slate, as I could not refer it to the stratification, as we are in the habit of doing in 

 the green slate, I suppose one is an effect of lateral pressure, the other of deposition. 



In summer I spent a few days upon the coast about Flimby ; there are a great 

 variety of granite pebbles along the beach there, and at Allonby ; but I was most 

 at a loss to trace the blue stones there in such quantity ; I suppose it is the Scotch 

 Whinstone, so much spoken of by the late Mr. Mc.Adam in his road -making. 



I am quite aware of the trouble you will experience in arranging your 

 multitudinous observations : in my limited ones I find considerable difficulty in 

 finding what I am in search of ; and the observations n(jt being all made, with equal 

 accuracy, makes it still more perplexing. I find two observations on Brathay Flag 

 quarry, which is one of our best sections in the upper slate. Taking a mean, what 

 I call the'plane of stratification, bears 85° E., dipping S. at an angle of 25°; the 

 hate or cleavage bearing 55° E., nearly perpendicular. 



