PEES.XWICH — ;CKAG-BEDS OF SXTPFOLK AND NOKFOLK. 471 



that is not denuded. Between Hasborough and Sherringham, the 

 latter usually lies at too low a level to be exposed. When it does 

 appear, the relations to the ISTorwich Crag and to the Westleton 

 beds remain constant, in the same way as at Coltishall, Wroxham, 

 and Thorpe. 



I have, in my last paper, noticed that the rich fossiliferous beds of 

 the Red Crag of Walton, Sutton, and Butley become poorer after 

 passing beyond that area, that at Chillesford the number of species 

 is much less, and that the same poverty characterizes the few pits 

 on the west flank of the Coralline ridge of Sudbourne. 



North of this ridge the Crag at Aldborough is still poorer ; but still 

 the fossils are all Eed-Crag species. At Thorpe the facias of the 

 fauna seems different ; but this is chiefly due to the difference in the 

 relative proportion of the species. There is not a single new species 

 of MoHusca ; but such species as are found on the beach of a sandj"- 

 bay abound. The Littorina littorea, scarce at Chillesford, Butley, 

 and Aldborough, is here abundant, as are also the Mya arenaria, 

 Mactra ovalis, and Cardium edule, whilst Natica, CerWimm, and 

 Turritella become much more common. At the same time some 

 fragmentary mammalian remains, vertebrae and teeth of flsh, and 

 fragments of Crustacea are also more numerous. At Sizewell the 

 Conovulus pyramidalis is a common shell. At Bulchamp and at 

 Easton Bavent freshwater shells increase in number, and the Corbi- 

 cula Jiuminalis* and th.e AstaHe borealis make their first appearance. 

 But of 43 other species of marine shells I have collected at Thorpe, 

 Sizewell, Bulchamp, and the neighbourhood of Southwold, there is 

 not a single species which is not found also in the Bed Crag. In 

 both also some species, such as the Tellina obliqua, T. lata, and 

 Purpura lapiUus, continue to be very abundant, and the Cyprina 

 islandica is common. In lithological character the only difference is 

 the greater extent of gravelly (flint) beds and the absence of the 

 ferruginous colouring, though that exists at Sizewell and Bulchamp. 

 Neither of these characters is of any importance. 



Probably Thorpe, Wangford, and Bulchamp (in part) may be re- 

 garded as the equivalents of the lower division of the Bed Crag, 

 whilst Sizewell and Easton Bavent should be referred to the upper 

 division or Chillesford sands. 



Tbis upper division is better exposed at Aldeby, where a large 

 addition is made to the number of species ; several new forms appear, 

 while some old forms of the Red and Coralline Crags reappear. 

 In the neighbourhood'of Norwich the Ehynchonella psittacea f comes 

 in, and on the coast at Sherringham the Tellina balthica is added to 

 the fauna. In the upper bed of the Norwich Crag at Bramerton and 

 Thorpe many of the species found in the lower bed are wanting, but, 

 with the exception of the accurate Hsts of fossils from the Bramerton 

 pits made by Mr. Reeve, we are yet without fully sufficient separate 

 lists of the two divisions of the Crag, whether in Norfolk or in 



* Mr. Bell has lately found this shell iu the Eed Crag at Waldringfield. 

 1- Also lately found by Mr. Bell in the Eed Crag at Shottisham. 



