724 MR. F. W. HARMEE ON THE CRAG OE ESSEX. [Nov. I9OO, 



A large proportion of the bivalves occur with both valves adherent, 

 but not specially in the position of growth. The deposit does not. 

 represent, in my opinion, an undisturbed sea-bottoin. The shells 

 present all the appearance of having been drifted ; they may have 

 been brought up by the scour of the estuarine tides, and buried 

 while living, or soon after death, in the tidal sediment. 



The fossils of the Chillesford Church pit are in a decayed condition, 

 resembling those found in freshwater strata, and contrast strongly 

 with the much better preserved shells of the marine portion of the 

 Crag. This is in harmony with the theory of the estuarine (brackish 

 water) origin of the Chillesfordian deposits. 1 When examined under 

 the microscope, the grains of sand composing the matrix in which 

 these fossils occur are seen to be less rounded than those of 

 the beach-sands of the Ked Crag. No glauconite occurs in the 

 Chillesford Sand, and grains of flint are rare in it (see Mr. Lomas's 

 Report, p. 743). In his opinion the material which composes this 

 deposit may have come from a distant source. 



For the latest of the Crag-deposits of East Anglia, that of Wey- 

 bourn and Belaugh, I have proposed the name Weybournian. 



These beds, which are characterized by the appearance for the 

 first time in the Crag basin of the recent species, Tellina balihica 

 (in the most extraordinary profusion), owing possibly to the opening 

 up of communication with some area, 2 perhaps the southern part of 

 the Baltic, where it had previously established itself abundantly, 

 contain the poorest, as well as the most recent and northern fauna 

 of any of the different horizons of the Crag. 



In my paper on the Pliocene deposits of Holland, 3 I suggested 

 that the pebbly gravels grouped by Searles V. Wood, Jun. and 

 myself as the 4 Bure Valley Beds' might possibly include deposits of 

 different ages. I now confine the term Weybournian to those only 

 of them in which, on the Cromer coast, and at Belaugh, Crostwick, 

 liackheath, and Wroxham, Tellina balthica is found ; and perhaps 

 to the upper part of the Crag-beds near Norwich, regarding the 

 uufossiliferous gravels associated with the Glacial beds in Norfolk, 

 together with the shingle of Westleton, Dunwich, and Halesworth 

 in Suffolk, as distinct (as stated by Prestwich), and probably as 

 Pleistocene. 4 



The mutual relationship of the different deposits is summarized 

 in the following synoptical analysis : — 



1 In his ' Report on the Marine Zoology of Strangford Lou»h ' Rep. Brit. 

 Assoc. (Dublin 1857) p. 110, Prof. Gr. Dickie noted a similar difference in the 

 condition of the shells dredged within the Lough (an extensive sheet of water 

 communicating with the Irish Sea by an exceedingly narrow channel), and of 

 those met with in the open sea outside it. 



2 See also H. B. Woodward, Mem. Geol. Surv. (1881) ' Norwich ' p. 37. The 

 occurrence of a number of characteristic Bed Crag shells (although derivative) 

 in gravel-beds on the Aberdeenshire coast tends to show that in the first 

 instance the Red Crag basin communicated with northern seas in that direction. 



3 Quart. Joum. Geol. Soc. vol. lii (1896) pp. 772-73. 



4 The separation between Pleistocene and Pliocene in East Anglia is, how- 

 ever, purely conventional, and must not be taken to indicate any important 

 break in the continuity of these deposits. 



