GEOLOGY 



Opinions differ with regard to the agent which formed the Boulder 

 Clay. That it was the product of ice-action is not seriously disputed, 

 but whether directly due to a mass, or masses, of land-ice, has been 

 questioned. Ice may have occupied the bed of the North Sea, and 

 spread thence in places inland as maintained by Mr. G. W. Lamplugh.' 

 Ice may also have come from north-eastern parts of England. That the 

 materials came largely from the north-west and north is to be inferred 

 from the Red Chalk, the Jurassic detritus, the carbonaceous fragments 

 which may have come from the Estuarine beds of Yorkshire, and the 

 occasional Carboniferous rocks. The matrix has received attention from 

 the Rev. Edward Hill, rector of Cockfield, and he observes that all the 

 minor materials may have had a westerly origin, and that they are for the 

 most part derived from Secondary strata.^ 



With regard to the question of an ice-sheet, it has been remarked 

 by Mr. Clement Reid that ' we should not forget, however, that an ice- 

 sheet flowing over a flat country, where the average temperature is near 

 the freezing point, is subjected to conditions entirely unlike those of an 

 alpine glacier flowing down a steep valley into a temperate climate. It 

 is, therefore, only with the ice-sheets of the Arctic regions, or with the 

 wide glaciers of Alaska, that we can profitably compare the ancient 

 glaciation of the North Sea basin.' ' 



The Boulder Clay occurs in patches along the eastern coast at 

 Gorleston, Somerleyton, Corton and Lowestoft, and is nowhere better 

 seen than in the cliffs at Kessingland and Pakefield, where it is about 20 

 or 30 feet thick and overlies, somewhat evenly and in gentle undulations, 

 the Middle Glacial sands and gravels. Where it rests on sands they 

 often appear to be undisturbed, but in places where stratification is pre- 

 served they show marked contortions, as was noticeable in cuttings near 

 Corton and Hopton on the new Yarmouth and Lowestoft direct railway. 



More striking evidences of disturbance are met with where the 

 Boulder Clay rests on beds of variable character. It is found indifferently 

 on any of the older formations, occupying slight hollows or occasionally 

 deep channels, the result of prior or contemporaneous erosion. Thus, a 

 deep channel in the Chalk at St. Peter's Quay, Ipswich, noticed by Mr. 

 Whitaker, was filled with i 27 feet of Drift.* 



Intruded tongues of Boulder Clay have been observed by Mr. F. J. 

 Bennett in the Chalk at Barrow, to the west of Bury St. Edmunds, 

 where a mass, 3 feet thick, extended some 20 feet into the Chalk.° 

 Again at Claydon the Boulder Clay has been thrust beneath the Crag 

 series.* 



» Geol. Mag. (1901), p. 142 ; see also H. B. Woodward, ibid. (1897), p. 485 ; Harmer, Proc. 

 Geol. Assoc, xvii. 465. 



- Sluart. Journ. Geol. Soc. Iviii. 179 ; see also Rev. R. A. Bullen, ibid. Ivii. 285. 



■^ ' Geology of Ipswich,' A'^jto/'ij/ SaVnc^, vii. 177. 



* 'Geology of Ipswich,' Geol. Sutvey, p. 118. 



' ' Geology of Bury St. Edmunds,' p. 1 1. 



" Whit.iker and others, 'Geology of the neighbourhood of Stowmarket,' p. 10 ; H. B. Woodward, 

 Ceol. Mag. (1897), p. 494. 



