S3 



Some of these icebergs, reaching the Scilly Isles from the east, 

 and bearing flint and greensand chert, and perhaps Sarsens, may 

 well have broken away from Dorset. 



It is known that river courses were greatly disturbed by 

 glaciation. Mr. Salter shows that drift gravels occur on the hills 

 above Portesham, near the Hellstone, about 600 feet above O.D. — 

 (it was here I found my Budleigh Salterton pebble) — and at lower 

 levels near Weymouth, pointing to another valley system now 

 almost entirely swept away. 



On the east side of Southampton Water, by Netley, and at 

 Lee-on-the-Solent, are thick beds of gravel containing implements 

 and frequent Sarsens. It signifies that the Frome at that time 

 continued to flow beyond the Solent towards what is now Selsea 

 Bill.— 52. 



Mr. Harmer calls " the case of Goring Gap " unique. He says 

 that at no other point south of the Little Ouse-Waveney depression 

 does water flow through the chalk range from one side to the other. 

 West of the Goring Gap the country (of the Thames) shows a lake- 

 like area of depression drained by a gorge of modern aspect 

 excavated transversely across the adjacent range of hills, and cut 

 down to a level of the plains on either side. The Thames originally 

 flowed north to the Wash, but this course must have been checked 

 by ice, and the river was compelled to cut through the chalk 

 ridge.— 53. 



Perhaps, when Mr. Harmer used the word unique, he had not 

 considered the case of the river Corfe, in Dorset. 



The Corfe river, which flows north into the Frome, is formed 

 by the union of the Steeple (or Wicken) Brook and the Byle Brook 

 after they have independently cut their way through the chalk ridge, 

 one on either side of Corfe Castle. Mr. Strahan considers this 

 double breach to have been initiated by a pair of streams engendered 

 on the northern slope of the Purbeck anticline, at a time when the 

 arch of the fold was unbroken and its drainage still of the normal 

 order, passing transversely over the chalk ridge. 



Mr. Osborne White thinks the two streams cannot boast such 

 an antiquity. 



Mr. Hudleston considered — (54) — that the eastern and western 

 affluents of the Corfe formerly united on the south of the chalk out- 

 crop and traversed it by a single channel, and that when this 

 channel had been cut down to about the level of the summit of 

 Castle Hill, or about 170 feet below the ridge on either side, the 

 two streams became separated, and commenced to carve out 

 independent gorges. But he offered no suggestion of the cause of 

 this sudden separation. 



Mr. O. White thinks the cause may have been a displacement 

 of their northerly ancient junction, under flood-plain conditions, 

 during a temporary cessation of the cutting down process. There 



52— P.G.A., xv., 279. 

 53— Q J G.S., lxiii., 470. 

 54— Guide to Wareham — Bright's, Ltd., Bournemouth. 



