80 S. V. WOOD, JITN., AND F. W. HARMER ON THE 



geological mapping, and by the numerous inland sections which 

 occur (so far as any remnants of the Contorted Drift can be traced), 

 is entirely in accordance with the state of things thus disclosed by 

 the Norfolk cliff, the interglacial denudation in question becoming 

 greater southwards, so far as Norfolk is concerned, and the inter- 

 glacial valleys excavated becoming deeper and deeper as this 

 denudation increases, so that instead of forming troughs in the 

 Lower Glacial beds only, as in the cliff-section, they are there cut 

 through the Lower Glacial beds altogether, and down into the Pre- 

 glacial floor, as we shall endeavour to show. 



Before doing this, however, let us see what light the coast-section 

 of East Norfolk and Suffolk affords upon the subject. From the 

 point where the Forest-bed ceases, east of Hasboro', the cliff is very 

 low, and the Preglacial floor, being beneath the beach, cannot be 

 seen. This district, however, is low and flat, and there are no 

 valleys beyond slight depressions of a few feet ; and from Eccles 

 to Winterton, a distance of 10 miles, there is no cliff at all. From 

 "Winterton southwards, so far as the Lower Glacial beds occur (which 

 is but slightly, owing to the interglacial denudation they have 

 undergone), they show no indication of having been deposited in 

 any of the valleys which the coast-line intersects ; for had they been 

 so they would (notwithstanding that the Preglacial floor is below 

 the beach, at an unknown depth and invisible) have exhibited a 

 tendency to dip into those valleys ; but they do not exhibit any 

 such tendency. As far south as Yarmouth the cliff is greatly ob- 

 scured by blown sand ; but south of Yarmouth the Contorted Drift, 

 denuded to a small thickness, shows itself horizontally at the base 

 of the cliff, until that again becomes obscured. For a considerable 

 distance inland of Yarmouth and to within about 4 miles of Nor- 

 wich the Preglacial floor is concealed at an unknown depth beneath 

 the waterline of the country, and the Middle and Upper Glacial 

 deposits, dipping into the valley by reason of the interglacial denuda- 

 tion of it which preceded them, conceal much of the Lower Glacial 

 in that part. 



South of Lowestoft, along the coast-section, the Contorted Drift 

 has been almost entirely denuded, and the Lower Glacial pebbly 

 sands underlying it have suffered from the same cause so much as 

 to occur but occasionally. Where they do remain, however, they 

 maintain their horizontality, and so far confirm the general uni- 

 formity of level which we believe the Preglacial floor to have 

 possessed in this part. So complete, however, has been the denuda- 

 tion of the Contorted Drift over the range of the Suffolk coast-section, 

 that its former spread over this area would not have been suspected 

 were it not for the thick outliers of it which remain far away in 

 South Suffolk, and one or two nearer exposures of it inland that 

 rise as bosses through the Middle Glacial sands which have been 

 bedded around them. For the same reason its spread over the Ked- 

 Crag area would be similarly unsuspected, inasmuch as, in all the 

 numerous sections of the Red Crag and its associated unfossiliferous 

 sands that are deep enough to show any formation resting on them, 



