120 PEOF. J. PRESTWICH ON^ THE RELATIOIST OF THE 



9. On. the Relation" of the Westleton Beds, or Pebbly Sands of 

 Suffolk, to those of Norfolk, and on their Extension Inland ; 

 with some Observations on the Period of the Pinal Eleva- 

 tion" and Denudation of the Weald and of the Thames 

 Valley, Sfc. By Joseph Prestwich, M.A., D.C.L., P.R.S., 

 P.G.S., &c. (Bead December 18, 1889.) 



PABT II. 



[Plate VII. ; see also the Map in Part III.] 



Page 



1. Classiflcatory Objects and Historical Summary 120 



2. Eange inland of the Westleton Beds north of the Thames : Suffolk 



(p. 124) ; Essex (p. 128) ; Middlesex (p. 136) ; Hertfordshire (p. 137) ; 

 South Buckinghamshire (p. 139) ; South Oxfordshire (p. 140) ; Berk- 

 shire (p. 141) 124 



3. Westleton Beds on the South of the Thames : Kent ; Surrey and 



Hampshire 143 



4. Possible extension of the Westleton Shingle beyond the Thames Basin 



into Wiltshire and Somei'set 143 



5. Relation of the Westleton Shingle to the Glacial Drifts of the Thames 



Valley 144 



6. Origin of the Shingle 145 



7. Conclusion — Elevation of the Westleton sea-floor ; Formation of the 



Gorge of the Thames at Goring^ Measures of Glacial and Post- 

 Glacial Denudation. Age of the Chalk and Oolitic Escarpments... 148 



1. Ohjects of the Pai^er ^c. 



In the first part of this paper * the relation of the Westleton Beds 

 in the Eastern Counties to the Crag Series on the one hand, and to 

 the Glacial Series on the other, was discussed. My object in this 

 part is to trace the extension of the former beyond the area of the 

 Crag, and to show that a Westleton Shingle-bed passes trans- 

 gressively over the Red Crag, the Tertiary strata, and the Chalk, 

 and ranges westward through the length of the London Basin, while 

 it rises to considerable heights above the Glacial Drifts and exists 

 independently of them ; and although it occupies only isolated 

 and detached outliers, if the relation of these outliers to the Pre- 

 Glacial Beds of Suffolk and Norfolk — the position of which has been 

 proved — can be determined, we shall then have a definite base by 

 which to correlate them and establish the order of succession and 

 relative age of the many Drift Beds of the London Basin. 



I purpose therefore to proceed step by step and to take each stage 

 separately, confining myself now to the oldest and highest stage, 

 where the distinctive characters of composition are best defined. 



^ Quart. Journ. Geol. Soc. for February 1890, p. 84. 



