Geology of the South East of Dorsetshire. 79 



Art. VI. Illustrations of the Geology of the South East of Dorset- 

 shire. By The Rev. W. B. Clarke, M.A. F.G.S. 



No. II. On the Strata between Durlstone Head and Old Harry 



Rocks. 



(Continued from Vol. i. n. s. p. 



The particular object of the paper on "The Vertical and 

 Curved Strata of Ballard Head," was to point out, in general 

 terms, the features of the district under examination, together 

 with the connection of its superficial phenomena, with those 

 of more distant localities ; an object which completely put 

 out of my power any attempt to describe the composition or 

 contents of the beds, now to be more especially considered. 

 That point, together with the proofs of my positions, was, of 

 necessity, reserved for this and the subsequent illustrations. 

 The present paper will, I hope, without further controversy, 

 convince Dr. Mitchell that he has assumed, in his criticism, 

 (vol. i. p. 587 — 591), a tone and language neither justified by 

 his little knowledge of the extent of my information, nor by 

 the manifest defect in his own. He will find that I have not 

 trusted " too implicitly to the authority of those persons who 

 have previously written on this part of the coast," — and that 

 the only "error" I have fallen into, has resulted from my not 

 having sufficiently trusted them, — a want of faith, which, on 

 his part, has not placed his own observations in the most fa- 

 vorable light. 



Dr. Mitchell says Durlstone Head is stated by me, to be 

 " composed of curved strata and breccia of Purbeck stone." — 

 Where did I ever say so ? Not, assuredly at p. 417, (Jig, 

 35). I merely pointed out that at 1 in that figure, the posi- 

 tion of the " overhanging, dark, curved strata, and breccia of 

 Purbeck stone, at Durlstone Head," were represented. Now 

 Dr. M. denies my general assumption of " curved strata and 

 breccia, in any part of Durlstone Head." He says the strata 

 " are not curved, but are in long parallel lines, separated from 

 each other by intermediate masses of clay." The clay has 

 nothing to do with the subject; for I was not describing the 

 contents of the beds, but the appearance of the coast from 

 the sea. The strata may be " in long parallel lines," and yet 

 be curved, for there are such things as parallel curves, whe- 

 ther long or short. But how any geologist with his eyes open 

 could possibly examine the coast from Swanwich to Durlstone 

 Head, and not see curved strata, is most marvellous ! Per- 

 haps, in all England, there are no such singularly striking 

 examples of curved strata, as are there evident to the most 

 casual observer. These curvatures are exhibited pretty ac- 



