GEOLOGY 



view, although recently opposed by Mr. Harmer, accords with the 

 general evidence along the East Anglian coast of successively newer 

 stages as we proceed from south to north. 



In the Norwich Crag we have a series of shelly sands, orange- 

 coloured and white pebbly sands and gravels, and thin seams and 

 extensive 'jambs' of laminated clay, to the more persistent masses of 

 which the name Chillesford Clay has been applied. It is indeed a 

 great series compared with the Coralline and Red Crags, for it has 

 been found to attain a thickness of nearly 200 feet in places, the thick- 

 ness increasing from the outcrop,' probably to some extent owing to 

 erosion of the strata during the Pleistocene period. 



In 1849 Prestwich described the sections at Chillesford near Orford 

 where the Red Crag with Scrobkularia is exposed in a stackyard, over- 

 lain by buff shelly sand and a band of loamy clay, to which the name 

 Chillesford Clay has since been applied.^ This clay occurs over some 

 extent of ground near Chillesford and at Iken. Somewhat disturbed and 

 rearranged beds of the clay overlie the Norwich Crag at Dunwich ; it 

 is not seen at Southwold, but thinner layers representing it occur in the 

 shelly sand and pebbly gravel at Easton Bavent. It occurs also at Cove- 

 hithe and Kessingland, at Beccles, near Herringfleet, Somerleyton and 

 Blundeston. It is not to be regarded as the highest portion of the 

 Norwich Crag Series, for in Norfolk it is represented only here and 

 there sometimes overlain by shelly gravel, and elsewhere apparently 

 replaced by the highest stage of the Norwich Crag, known as the 

 Weybourn Crag and Bure Valley Beds. Here we enter the region of 

 controversy, and it will be sufficient to mention that this highest group 

 is succeeded in Norfolk by the Forest Bed Series, which is represented 

 in places on the Suffolk coast. 



Following Mr. Harmer we may regard the Norwich Crag as 

 extending from the neighbourhood of Thorpe or Aldringham Common 

 near Aldeburgh to Dunwich, Southwold, Bulchamp and Wangford, and 

 to the Waveney valley near Bungay and Beccles. 



These include the most famous localities for fossils, but in many 

 parts of Suffolk, as in Norfolk, we find few or no fossils, as in the 

 Minsmere valley at Darsham and Y oxford, and in the Blyth valley at 

 Thorington, Halesworth and Walpole. In some cases no doubt the 

 shells have been dissolved away. Thicknesses of 105 feet at Saxmund- 

 ham, 133 at Leiston, 147 feet at Southwold and 80 feet at Beccles have 

 been assigned from the evidence of well borings to the Norwich Crag, 

 without including certain pebbly gravels which at any rate at Southwold 

 and Beccles most likely belong to the series.^ 



* See Whitaker, G«/. Mag. (1895), p. 464; Harmer, ^art. Joum. Geol. Soc. Hi. 767; Pm. 

 Geol. Assoc, xvii. 443. 



^ Sluart. Joum. Geol. Soc. v. 345 ; xxvii. 336, 337. See also Harmer, ibid. liv. 309 ; Ivi. 708, 

 721 ; and Reid, ' Pliocene Deposits of Britain,' p. 100. 



^ Reid, ' Pliocene Deposits of Britain,' p. 201 ; and H. B. Woodward, 'Geology of the country 

 around Norwich,' Geo/. Survey (1881), p. 31. See also Prestwich, ^art. Joum. Geol. Soc. xxvii. 343, 



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