500 PLEISTOCENE. 



and freshwater remains were no doubt brought down by a river. Similar beds 

 were seen at High Paull Cliff. South of the Humber the gravel is shown near 

 Ulceby, at Great Coates and other places.^ 



These marine gravels can be traced round the ancient bay of Holderness, which 

 was bounded by Chalk cliffs. They are probably of the same age as the 

 March gravels, but possibly older than the Basement Clay, or intermediate 

 between it and the Purple Clays ; but these fossiliferous beds are not shown in the 

 coast-section. At Speeton there is a sandy shell-bed beneath the Lower Purple 

 Clay which corresponds with the Marine gravels of Kelsey Hill ;' and at Aby 

 near Claythorpe in Lincolnshire, similar shelly gravels occur. •^ At the former 

 locality the following beds are exposed :* — 



Upper Purple Clay 30 feet. 



Sand and Gravel 5 >) 



Lower Purple Clay 10 >> 



Sandy Shell-bed 16 ,, 



The cliff at Cleethorpes, about 40 feet high, is the only cliff in Lincoln- 

 shire, and it exhibits a purple stony Boulder Clay which seems to correspond with 

 the higher divisions of the Holderness coast— the Hessle Clay and the Upper 

 Purple Clay. 



Inland in Lincolnshire the Hessle Clay is usually a reddish-brown mottled clay, 

 while the Purple Clays are blue and grey. They occupy low levels on the western 

 edge of the Fenland, and to the east of the Lincolnshire Wolds." The Chalky 

 Boulder Clay occupies a tract between the Chalk Wolds and the Cliff range 

 (Oolites) ; it is seen around Corby, Ponton, Horncastle, Tattershall, etc. There 

 are no clear sections showing the junction of Chalky Boulder Clay with the newer 

 Boulder Clays. The Hessle Clay is shown in brickyards near Alford. Coarse 

 flint-gravel, with boulders of Chalk, occurs in places as at Wrawby; similar gravel 

 occurs at Wells, in Norfolk. 



In the Stoke cutting, south-west of Great Ponton, on the Great Northern 

 Railway, and south of Grantham, in Lincolnshire, a section was exposed, showing 

 Boulder Clay that contained an enormous irregular mass of Oolitic rock (Lincoln- 

 shire Limestone), 430 feet long, and, at its deepest part, 30 feet thick. It was much 

 broken and disturbed, but the parts retained to some extent their relative position, 

 and although distinctly isolated, the mass had not been far removed from its original 

 site.'' Other re-deposited masses of Oolitic rock and Marlstone have been noticed 

 in the district, sometimes of sufficient bulk to be quarried. 



At Roslyn Hole or Roswell Hill, near Ely, a large transported mass of Chalk 

 rests in places on the Kimeridge Clay.'' This mass forms part of the Boulder 

 Clay, which is probably the same as the Chalky Boulder Clay of Norfolk and 

 Suffolk, although the large re-deposited masses of Chalk met with in the Norfolk 

 cliffs occur in the Contorted Drift. (See sequel.) The Boulder Clay covers much 

 of the country west of Cambridge, it skirts the Chalk escarpment, and occurs in 

 isolated patches at various levels, as at Gog Magog and Balsham.^ (See Fig. 

 68, p. 411.) 



1 Prestwich, Q. J. xvii. 446; Reid, Geo!. Holderness, p. 51. 



2 Reid, op. cit. p. 69. 



3 Jukes-Browne, Geol. East Lincolnshire (Geol. Surv.). 



* Lamplugh, G. Mag. 188 1, p. 177. 



5 Reid, Geol. Holderness, pp. 35, 43 ; Jukes-Browne, Q. J. xxxv. 399, xli, 

 124, 131 ; Geol. S. W. Lincolnshire, p. 85. 



^ J. Morris, Q. J. ix. 318 ; Judd, Geol. Rutland, etc., p. 246 ; Jukes-Browne, 

 Geol. S. W. Lincolnshire, p. 81. 



' O. Fisher, G. Mag. 1868, p. 407 ; T. G. Bonney, Ibid. 1872, p. 403 ; 

 Skertchly, Geol. Fenland (Geol. Surv.), p. 238. 



* Jukes-Browne, Post-Tertiary Deposits of Cambridgeshire, 1878; Penning and 

 Jukes-Browne, Geol. Cambridge, p. 73 ; Penning, Q. J. xxxii. 191. 



