GEOLOGY 



EOCENE 

 THANET BEDS 



The oldest Eocene strata in this country are the Thanet Beds, and 

 their presence in the neighbourhood of Sudbury was made known in 1874 

 by Mr. Whitaker. Above the Chalk he observed at Ballingdon, a suburb 

 on the Essex side, 14 feet of green clayey sand, which in all probability 

 represents the Thanet Beds/ Traces of the same deposit, sometimes 

 with green-coated flints, have also been observed by him At Cosford 

 Bridge and Kersey Mill in the Brett valley, and at Somersham, Little 

 Blakenham, Claydon, Barham, Bramford and Ipswich. 



Nucula and Cardium are the only fossils which have locally been 

 found in the strata. 



READING BEDS 



Overlying the thin representative of the Thanet Beds, and other- 

 wise persistent in Suffolk, is the variable group of strata known as the 

 Reading Beds. They comprise alternations of mottled clay, brown and 

 grey clay, grey and green sand, with occasional masses of concretionary 

 sandstone of the nature of greywethers. Black flint pebbles occur here 

 and there, but not in prominent layers ; and no fossils have been ob- 

 served in the strata in Suffolk. The outcrop of the group can be traced 

 by means of pits and borings from Sudbury to Kersey near Hadleigh 

 and the neighbourhood of Ipswich, where the thickness is reckoned by 

 Mr. Whitaker at 37 feet. The thickness however varies like the strata, 

 even within short distances, being from 43 to a little over 60 feet in the 

 neighbourhood of Felixstow, 36 feet at Trimley, 27 to 34 feet near 

 Woodbridge, as much as 70 feet at Southwold, and nearly 80 at Leiston. 

 In these localities our information is derived wholly from records fur- 

 nished by well-sinkers. The main mass of the Reading Beds extends 

 to Saxmundham and Lowestoft, but not so far inland as Beccles. 



The possible occurrence of an outlier of Reading Beds beneath 

 Drift and Crag at Hoxne has been suggested by Mr. W. H. Dalton, 

 and he records the occurrence of ' plastic blue loam ' near Halesworth 

 which 'may belong to this series'; but the evidence in both cases is 

 questionable.^ In a well made at Brettenham it is possible that Reading 

 Beds occur beneath the Drift, but Mr. Whitaker, who has published 

 the section, does not favour this view.^ 



The Reading Beds having a narrow outcrop and being much con- 

 cealed by newer strata enter but little into the surface features of the 

 county. The clays are worked for brick-making near Sudbury, Bram- 

 ford and Ipswich, and the sandy beds are water-bearing. 



At Stoke near Ipswich Mr. Whitaker noticed a few feet of sandy 



' Stuart. Joum. Geol. Soc. xxx. 401. 



» See ' Geology of the Country around Halesworth and Harleston,' Geol. Survey (1887), pp. 3. 



37, 38- 



^ ^art. Joum. Geol. Soc. lix. 



