INTRODUCTION, 



M»7 



Counting specimens us well as species, the percentage of iioiMu'rii and recent 

 forms in this division is considerably greater, and of southern and extinct forms 

 considerably smaller than in the earlier horizons of the Red Crag. The tyi)ical 

 Neptnuea anliqna of British seas begins to l^e more connnon, while the proportion 

 of sinistral forms of that genus, as compared with that of the dextral ones, 

 is less. 



It will be seen fi-om the al)ove remarks that my views on the Red Ci'ag diffei- 

 widely from those of the late Sir Joseph Prestwich, who divided the latter into 

 two parts only, in the lower ot" which he grouped the very different faunas of 





-HalesworthJ^-~^ — ^1 





Fig 4. MAP SHOWING 

 THE RELATIVE AREAS 



OCCUPIED 



BY THE DIFFERENT ZONES 



OF THE 



EAST ANGLIAN CRAG. 









-FRAMLINGHAM,', ' 1 '\ " 



avcnt 

 'SOUTHWOLD 



Dunwich 



Suilc of Miles 



■ I I I I I I I VtV^ 

 r-'-r ^ i ' 1 ' 1 ' i'iN d/.,TH 



I I I I I T 



SAXMUNDHAM 





Fig. 4 (reproduced by permission of the Council of the Geological Society).— F. W. H. 



Walton-on-tlie-Naze, Sutton, Bawdsey, Sudbourn and Aldeburgh,^ 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 acidulated water) and of the Chillesford beds. The Norwich 

 Crag, in Avhich he included the Wey bourne beds containing Tellina balthtca, 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. 



The beds met with in the Dutch borings, for which I have adopted the term 



' He remarks, " I can see no distinction in the organic remains from the base of the Red Crag 

 to the top of the lower division," Quai-t. Journ. Geol. Soc, vol. xxvii, p. 354, 1871. 



