308 MB. p. W. HAEMER ON THE LENHAM BEDS [Aug. 1898^ 



26. The Pliocene Deposits of tJie East of England : The Lenham 

 Beds and the Coealline Crag. By E. "W. Harmer, Esq., E.Gr.S, 

 (Eead March 9th, 1898.) 



I. Introditction. 



The Pliocene deposits of the East of England have been studied for 

 many years, and by many competent observers, but, unfortunately, 

 no general consensus of opinion has been arrived at, either as to 

 their systematic arrangement, or the conditions under which they 

 originated : the views, for example, of Sir Joseph Prestwich, which 

 have obtained considerable acceptance, differing in many important 

 respects from those of the equally eminent authorities Mr. Searles Y. 

 Wood and his son. 



Prestwich, in his well-known paper,^ divided the Coralline Crag 

 into eight constant and determinable zones, and, on the other hand, 

 regarded the Eed Crag as formiug two divisions only : the lower, 

 including the deposits of Walton-on-the-Naze, Sutton, Bawdsey, 

 Butley, Sudbourne, and Aldeburgh,^ and the upper, consisting of 

 what he originally called ' the unfossiliferous sands of the Crag ' 

 (now believed to be a part of the deposit which has been deprived 

 of its shells by the infiltration of water containing carbonic acid)^ 

 and of the Chillesford Beds. The Norwich Crag, with which he 

 grouped some deposits containing Tellina halthica, he held to be 

 equivalent, partly to his lower (namely, to the Crag of Walton, 

 Sutton, Butley, etc.), and partly to his upper or Chillesford 

 division.* 



I still hold, for reasons to be given hereafter, that there is no 

 sufB.cient evidence for dividing the Coralline Crag into the eight 

 zones proposed by Prestwich ; indeed, I now believe that the 

 tripartite arrangement, formerly adopted by Mr. Wood, jun., and 

 myself," can be no longer maintained, and that the Coralline 

 Crag is practically one formation, of the same character, and 

 deposited throughout under similar conditions. With a series of 

 beds 60 feet in thickness, there is, however, necessarily some 

 difference in age between those which occur at any one place in 

 vertical section. 



As to the Eed Crag, the facts which I propose to offer in a 

 succeeding paper will show, I think, that the division of this 

 formation into four zones, proposed by S. Y. Wood, sen., in 1866,® 

 represented by the deposits occurring at Walton, Sutton, Butley, and 



1 Quart. Journ. Geol. Soc. vol. xxvii (1871) p. 121, fig. 4. 



2 Ibid. p. 354. 



3 Wood & Harmer, and Whitaker, ibid. vol. xxxiii (1877) pp. 75 & 122. 

 * Ibid. vol. xxvii (1871) pp. 471-73. 



5 Suppl. ' Crag Molkisca,' Introd. p. iii, Monogr. Palaeont. Soc. 1872. 

 5 Quart. Journ. Geol. Soc. vol. xxii, p. 538. 



