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