Ch. XXI.J ALLUVIUM OF WEALD VALLEY. 297 



of the chalk and its flints in the deep valleys of the Forest 

 ridge. Indeed, if we adopted the diluvial hypothesis of Dr. 

 Buckland, we ' uld expect to find vast heaps of broken flints 

 drifted more frequently into the valleys of the Gaultand Weald 

 clay, instead of being so frequently confined to the summit 

 of the chalk downs. On the other hand, it is quite conceivable 

 that the slow agency of oceanic currents may have cleared 

 away, in the course of ages, the matter which fell into the sea 

 from wasting cliffs. The reader will recollect our account of 

 the manner in which the sea has advanced, within the last cen- 

 tury, upon the Norfolk coast at Sherringham *. 



No. 72. 



Section of cliffs west of Sherringham, 



a, Crag. b } Ferruginous flint breccia on the surface of the chalk, 



c, Chalk with flints. 



The beach, at the foot of the cliff, is composed of bare chalk 

 with flints, as is the bed of the sea near the shore. No one 

 would suspect, from the appearance of the beach at low water, 

 that a few years ago beds of solid chalk, together with sand 

 and loam of the superincumbent crag, formed land on the very 

 spot where the waves are now rolling ; still less that these same 

 formations extended, within the last 50 years, to a considerable 

 distance from the present shore, over a space where the sea has 

 now excavated a channel 20 feet deep. 



As in this recent instance the ocean has cleared away part of 

 the chalk, and its capping of crag, so the tertiary sea may have 

 swept away not only the chalk, but the layer of broken flints 

 on its surface, which was probably a marine alluvium of the 



* Vol. i, p. 268, and Second Edition, p. 307. 



