334< The Rev. D. Williams on the Killas Group of 



strict must have been under the sea, and subjected to the 

 powerful action of denuding causes, by which the upturned 

 edges of the disturbed beds were worn to an even surface, 

 and the existing masses of old red conglomerate washed into 

 the hollows; the mountain limestone was deposited on the 

 worn and even surface of these older rocks*." Mr. Hopkins 

 states previously, " The mountain limestone reposes uncon- 

 formably on the older formations, which, within the limestone 

 band, occupy the surface f." At the close of a paper published 

 in the London and Edinburgh Philosophical Magazine for 

 July 1842, but dated May 17th, and communicated to the 

 editors before Mr. Hopkins's Memoir was read at the Geo- 

 logical Society, I indirectly adverted to the views I enter- 

 tained of the position of the Devon and Cornwall beds ; and 

 in an announcement of them at the meeting of the British 

 Association, held at Manchester in the same month, I was 

 constrained to invoke an elevation and submergence of the 

 old red sandstone prior to the deposition of the mountain 

 limestone, to as great and perhaps greater extent than was 

 contended for by Mr. Hopkins %. Mr. Sharpe has also ob- 

 served an unconformity of strike and dip between the old red 

 sandstone and mountain limestone above Kirkby Lonsdale, 

 the angle of dip varying five degrees, and the strike fifty : 

 " further westward," he observes, " the want of conformity 

 is still more manifest," the variation in strike amounting to 

 seventy degrees, and lower down the valley of the Lune 

 other instances still more remarkable are adverted to. Mr. 

 Sharpe concludes "there is abundant evidence of both the 

 old red sandstone and Ludlow rocks having been dislocated 

 before the accumulation of the mountain limestone, as the 

 limestone of Kendal Fell rests in a nearly horizontal posi- 

 tion upon the upraised edges of an anticlinal ridge of Lud- 

 low rock, from which a covering of old red sandstone has 

 been partially denudated §." Now, if a break or interruption 

 in the succession actually exists between them, as is indicated 

 by such hard junction in the west of England, and uncon- 

 formity in the north, the interval implied might of course be 

 sufficiently capacious for the reception of all the Devonian and 

 Cornish rocks, and others which may be elsewhere still above 

 them. 



* Geological Proceedings, No. 90, p. 760 [or Phil. Mag. S. 3. vol. xxi. 

 p. 472]. 



f Ibid. p. 757 [or Phil. Mag. S. 3. vol. xxi. p. 469]. 



| Transactions of the Sections, p. 61. 



§ Geological Proceedings, No. 85, pp. 605 and 607 [or Phil. Mag. S. 3 

 vol. xxi. p. 558, 559, 561]. 



