145 



From Professor Phillips. 



Dear Sir, — 



I am much obliged by the receipt of your notices concerning the distribu- 

 tion of Boulders from various parts of the Cumbrian Mountains, which are very 

 satisfactory, and will be incorporated in a general view which I mean to oflfer to the 

 next meeting of the Association, of the Phenomena of this nature in the west of 

 England. 



I have also been much gratified by the specimen of red crinoidal lime- 

 stone from the "Old Red" Conglomerate of Kirkby Lonsdale. In my long 

 residence at Kirkby Lonsdale, I also found Limestone fragments in that 

 singular rock, and experienced exactly the same hesitation as to its geo- 

 logical place.* These doubts I have discussed at length in my new volume on 

 Yorkshire Geology, now passing through the press, and from the whole of the 

 evidence at this and the other stations where that rock occurs, I conclude it to be 

 of the Old Eed as the most pi-obable of the possible results, but 1 know no one instance 

 of real and actual superposition, except perhaps at Dacre Castle. There are 

 absolute and good arguments for this antiquity, and jjerhaps none positive against 

 it. The Limestone is puzzling, however, and so I always thought it. 



Can you give me a notion of your results as to the general direction of slaty 

 clearage in your country ? I mean as compared to the E. W. N. <L S. , also as to its 

 relation to the planes of stratification ; is it rectangled to them, (oot quite I think) ; 

 have you noticed any general directions to the joints, fissures, or "Backs" in the 

 slate ? is there any "bate" besides the clearage, (as we have in Craven always) ? 



Ever yours truly, 



JOHN PHILLIPS. 



This last question addressed to Otley, by Phillips, regarding cleavage, 

 brings me to notice what I cannot but consider the best piece of 

 geological work ever done by Otley, and that by which he ought to be 

 known by all English geologists. No one with even a slight knowledge 

 of rocks, can fail to see the difficulty which frequently attaches itself to 

 the distinction between bedding and cleavage in such highly contorted 

 strata as those of the Skiddaw Slates. The bedding lines are those of 

 original deposition, and are frequently marked by bands of slightly 

 different colour, (called stripes by the old writers), but the planes of 

 cleavage which frequently cause the rock to split readily across the 

 bedding have been produced, subsequently, by great lateral pressure, the 

 particles of the rock being made to take up new positions, and being 



* In former letters Otley had, from the presence of such fragments of limestone 

 in the Conglomerate, doubted whether the latter really underlaid the Carboni- 

 ferous Limestone. 



