GEOLOGY 



SUFFOLK forms part of the East Anglian plain, and consists 

 almost wholly of an undulating region which rarely attains an 

 elevation of 400 feet. The greater portion of the county rises 

 from 80 to 200 feet above sea-level ; there are no prominent hills, 

 and even the district between Stowmarket and Harleston, to which the 

 term ' High Suffolk ' has sometimes been applied, lies below 200 feet. 

 The highest ground is between Haverhill and Bury St. Edmunds, and 

 this reaches 417 feet at Rede. The great alluvial tract of the Fenland 

 extends to Mildenhall in the north-western portion of the county, and 

 constitutes a lower plain. 



The main features are those of the river valleys, notably along the 

 lower courses, which widen out into the pleasant estuarine waters of the 

 Deben, Orwell and Stour, or expand — as in the case of the Waveney 

 where it joins the Yare — into the brackish water ' broad ' known as 

 Breydon Water. 



The coast line is nowhere protected by hard rocks, the cliffs being 

 formed of loose sands, gravels and clays, which yield so readily to the 

 combined attacks of land-springs and sea that the losses have been dis- 

 astrous. 



The geological structure of Suffolk is comparatively simple. The 

 Chalk forms the foundation of almost the entire county. Its base would 

 be reached just below ihe fens of Mildenhall, and it is inclined gently 

 towards the south-east. Thus at Culford near Bury St. Edmunds it has 

 a thickness of 526 feet ; at Stowmarket and to the south-east it is over 

 800 feet. It forms part of that shallow trough or syncline known as the 

 ' London Basin,' which in the southern and eastern parts of the county 

 where the Chalk is thickest supports a mass of Eocene strata. These 

 appear at the surface at Sudbury and Ipswich, and have been proved in 

 borings at various places, including Southwold and Lowestoft. 



Stretching irregularly across the worn surfaces of the Eocene in the 

 southern, and on to the Chalk in the north-eastern parts of the county, 

 are found the several divisions of the Crag formation for which Suffolk 

 is especially famous. Nowhere else in England is there a better hunting- 

 ground for the collector of fossils than that portion of the Crag district 

 which extends from Felixstow to Aldeburgh and inland to Ipswich and 

 Woodbridge. There in many a pit shells and other organic remains in 

 great abundance and variety may at all times be obtained. 



These richly fossiliferous strata have been partially destroyed and 

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