750 THE PLIOCENE DEPOSITS OE HOLLAND. [Nov. 1 896. 



a level, according to Mr. Reid, of about 600 feet above the sea. 1 

 This elevation, thus increasing to the south or south-west, was 

 accompanied by a subsidence of the northern, or rather of the north- 

 eastern, portion of the East Anglian area. Sir Joseph Prestwich 

 found the base of the Crag at Sutton, where it rests on the London 

 Clay, to be at one place 8 feet, and at another 20 feet above the high- 

 water mark of the estuary of the River Deben. 2 Mr. Whitaker 

 has given the results obtained in three borings near Orford, about 

 8 miles to the N.E. of Sutton, in two of which it was reached at 

 26 feet below Ordnance-datum, and in the third at a less depth. 3 

 At Aldeburgh, 5 miles farther to the 1NT.E., I bored last autumn into 

 the Crag 20 feet below the water-line, without reaching the London 

 Clay, and I was informed that former borings had been carried 

 down 30 feet with a similar want of success. 4 Farther north, at 

 Saxmundham, the junction of the Crag with the Eocene beds is 

 said by Mr. W. H. Dalton to occur at a depth of 60 feet, 5 and at 

 Southwold, 11 miles N.E. of Saxmundham, at about 140 feet below 

 the sea-level. 6 (See section, fig. 1, p. 751). 



It has been stated that in a boring in the harbour at Lowestoft 

 the Chalk was met with, 80 feet below high-water mark. If this 

 be correct, there exists under that town a submarine ridge rising 

 through both the Eocene and the Pliocene beds, 7 but at Yarmouth, 

 40 miles N.N.E. of Sutton, the bottom of the Pliocene basin occupies 

 nearly its normal position, the surface of the London Clay being 

 there found at a depth of 150 feet below the sea-level. 8 



If the Crag beds are present under Yarmouth, as seems not im- 

 probable, there is a difference in the level of the base of these 

 deposits of 180 feet in about 40 miles. The section (fig. 1) will 

 show that, although the surface of the Chalk along this line is ex- 

 ceedingly irregular, the base of the Crag dips northward in a fairly 

 uniform manner. 



The section (fig. 2, p. 753) from Norwich to Yarmouth shows 

 that the Pliocene beds dip similarly from W. to E. Near the 

 Cavalry Barracks at Norwich, the Crag sands rest on the Chalk 

 at about 45 feet above the Eiver Wensum. At Bramerton, 4 miles 

 to the E.S.E., they are but little above the water-level, while beyond 

 that place they dip below it. The line of junction of the Chalk 



1 Op. cit. p. 45. 2 Op. cit. p. 116. 



3 Dalton & Whitaker, Mem. Geol. Surv. Aldeburgh, 1886, p. 53. 



4 Sir Joseph Prestwich (Quart. Journ. Geol. Soc. vol. xxvii. 1871, p. 496, 

 pi. xx.) shows in one of his sections the junction of the Coralline Crag and the 

 London Clay at Aldeburgh as considerably above O.D., but this is inaccurate. 



5 Dalton & Whitaker, Mem. Geol. Surv. Aldeburgh, 1886, p. 53. Mr. 

 Whitaker gives, on hearsay evidence (p. 52), a depth of 130 feet below 

 Ordnance- datum for the base of the Crag at Leiston, but is this correct ? 



6 Whitaker, Mem. Geol. Surv. Southwold, 1887, p. 78. 



7 Mem. Geol. Surv. Southwold, 1887, p. 4. The Lowestoft boring is cited 

 by Mr. Whitaker on the authority of Mr. A. A. Langley. The presence of the 

 Chalk so near the surface at that place appears improbable. May it not have 

 been the Chalky Boulder Clay that was met with ? It is known that this deposit 

 occurs in the Waveney Valley at a considerable depth below the alluvium. In 

 the section (fig. 1) I have shown the Chalk at Lowestoft with a query. 



s Quart. Journ. Geol. Soc. vol. xvi. (1860) p. 450. 





