WESTLETON EEDS TO THOSE OF NORFOLK, ETC. 95 



renee of this one shell is a very insufficient palceontological dis- 

 tinction. 



Where the Chillesford Clay is absent, evidence of its former pre- 

 sence often exists at the base of the Pebble-beds in the form of 

 pebbles of clay, derived probably, in some cases, from that clay. 

 The instance recorded by Mr. Woodward in the typical Wroxham 

 district, of a gravelly bed with clay pebbles at the base of beds of 

 buff sands and pebbly gravel (the Bure-Valley Eeds*) in a cutting 

 near the station may be of this character. It is easy, therefore, 

 to imagine that, owing to this removal of the Chillesford Clay, the 

 Bure-Valley Crag may often be in contact with beds of the age of 

 the Norwich Crag, and that in the case of beds so much alike it 

 would be difficult to detect the line of separation, while" the fossils 

 of the lower beds would be apt to get mixed with those of the 

 upper one. 



Therefore, while I admit the value of the distinction drawn by 

 Messrs. Wood and Harmer between the Norwich Crag and the Bure- 

 Valley Pebble-beds, I do not think that either the pala^ontological 

 or stratigraphical proofs respecting the position of these Pebbly 

 Sands are so well defined and certain in the Bure-Valley district as 

 they are in the Westleton and Southwold districts, or so fitted to be 

 taken as the type of a wide-spread geological zone. Eor these 

 reasons, although the term of Bure-Valley Crag or Beds may be con- 

 veniently applicable to a local fossiliferous condition of the Pebbly 

 Sands, I do not think it to be, for a general term, so suitable as the 

 term of " The Westleton and Mundesley Beds J' 



This is the term that in 1881 1 I proposed to adopt in place of my 

 original terra of "Westleton Sands and Shingle," in 1870, for the 

 reason that when a particular series of strata presents, in adjacent and 

 conterminous areas, markedly different palceontological and structural 

 characters, it may be convenient, as in the case of the " Woolwich 

 and Reading Beds," to give them a double gcogi'aphical name, indi- 

 cative of the localities where the two types are res])ectively best 

 developed, and their relation to the overlying and underlying strata 

 best exposed. It will, however, be convenient, wdieii speaking of 

 the inland continuation of these beds, to use merely the term of 

 " Westleton Beds or Shingle," as then w^e shall have to deal with that 

 type of them alone. 



§ 4. The Strvctvre and Pala'oviohf/ical Characters of the Westleton 

 and Mundesley Beds, in Norfolk and Suffolk. 



Before proceeding with the inland range of these beds, I will 

 describe more fully my view of the relation they hold — on the one 



* Similar cases, having reference to this and other underlyinof clay-beds of 

 the Forest-bed series, are common in tlie const sections, and nrc recorded by 

 Mr. C. Reid (op. at. p. 15 &c.) and by myself (Quart. Jouru. Geol. Soc. vol. 

 xxvii. p. 405). 



t This paper is an amplification of the one then read before the British 

 Association, and which appeared only in Abstract. 



