362 SECTIONAL TRANSACTIONS.— C. 



the stage represented by Barrow's High Level (Pliocene) Gravel of the London 

 Basin, which seems to belong to a period prior, as he believes, to the great 

 denudation. 



This, then, would be the western embayment of the North Sea. 



A movement en bascule seems to have ensued, resulting in a general but 

 intermittent uplift on the English side and along the axis of Artois, with a 

 complementary slow depression of Northern Belgium and Holland. Great 

 denudation of the British Diestian, and probably some Miocene, ensued, and 

 the Coralline Crag, probably an offshore shoal in 20 or 30 fathoms of maximum 

 depth, was accumulated upon an eroded surface of Lower Eocene; but its 

 gravelly base obtained the coarse scourings of London Clay, ( ?) Miocene, and 

 fossiliferous concretions of a sandstone near to the Diestian in age. 



On the Belgian side depression seems to have been almost continuous. 



The Coralline Crag was uplifted and subjected to severe sub-aerial and marine- 

 erosion, and the Red Crag overlapped it on the English and Belgian sides. 



With the earliest Red Crag, that of Walton-on-the-Naze, the record becomes 

 practically continuous. Steady uplift was taking place in the south, throwing 

 the ccast-line farther and farther north. Harmer recognises three stages, but 

 many more could be distinguished by the progressive changes in the fauna — 

 the elimination of Southern types and the incoming of Northern. 



The Norwich Crag comes in north of a ridge of Coralline Crag at Aldeburgh 

 and appears to represent a very slightly more modern phase than the Red Crag 

 flanking the ridge on the south. 



Chillesford Sand and Clay surmount the Red and Norwich Crag from 

 Essex upward. 



Harmer regards them as the deposits of a winding estuary of the Rhine. 



A renewal of the ' Crag ' type of deposition, the Weybourn Crag, with 

 Teltma balthica, was succeeded by a definite estuarine series, the Cromer Forest 

 Bed. It begins with the Freshwater Bed, in which a flora comparable to that 

 of Norfolk to-day is found. This is followed by a marine deposit with Arctic 

 shells, and above that a second freshwater bed with an Arctic flora. 



This series may rest directly on the Chalk, an effect of the continued upward 

 tendency on the English side of the sea. 



In Holland the whole Pliocene series is probably present, and the great 

 thickness of comparatively shallow-water deposits prevailing down to 1,100 feet 

 at Utrecht bespeaks a continual downward tendency of the Low Countries. 



The evidences of Pliocene conditions further north are extremely scanty, in 

 fact only near Haitlepool, where Trechmann has found a pre-GIacial plant bed, 

 is there any relic of Pliocene deposits in their native position. 



At Sheringham Mr. Stather has found a block, doubtless from the Drift, 

 of Red Crag of about Newbournian date of a type unknown elsewhere. 



In Holderness the Drift has yielded remanie. fish remains evidently derived 

 from the Red Crag, and in Aberdeenshire in the Slains Gravels Jamieson found 

 a large suite of rather fragmentary shells of mainly early Red Crag facies, 

 mingled with some undoubted Pleistocene forms. 



The Cromer Forest Bed stage is the latest pre-Glacial stage recognised in 

 Ea.st Anglia, but in Yorkshire a well-defined cliff-line bounding a broad plain 

 of marine erosion is traceable, which appears to be, in part at least, of later date. 



The cliff begins at Sewerby between Bridlington and Flamboro Head, and 

 has been traced by Mr. Crofts and myself round to Hessle, near Hull. The 

 corresponding beach has been seen at each end. Borings have enabled the old 

 sea-floor in front to be charted and contoured. 



The next phase was a retreat of the sea and formation of sand dunes along 

 the foot of the cliffs. The geological date is indicated by the occurrence of 

 Elephns antiquiis^ ^Rhinoceros leptorhiniis and Hippopoiamus in the deposits. 



This fauna accompanies implements of Chellean type in the South of 

 England. 



The next episode was the arrival of a great ice-sheet having its radiant 

 point in the neighbourhood of the Gulf of Bothnia. This appears to have 

 displaced the water from the whole of the North Sea as far south as the 

 coast of Essex, if no further. 



Several retreats and readvances took place, and the final retreat can be traced 

 with great detail and precision by the drainage phenomena developed along 



