14 



receive the sediment, while where walls exist the deposit is limited 

 to the space on either side of the river between the walls. Another 

 observation shows that the river, when not embanked, is constantly 

 shifting? its channel, for here one good turn deserves another. 

 A bend in the river (from whatever manner first formed) becomes 

 more crooked, because the velocity of the current is thrown into 

 the bend which it tends to still more undermine, while at the point 

 where the velocity is diminished there will be a tendency to deposit 

 silt. So in the case of the Stour there are repeated instances of 

 the shifting of the river's channel, and of its finding its way 

 through former deposits of silt. In a tidal river another force has 

 to be taken into account. The tide will rise and fall twice in 

 twenty-four hours, consequently the downward tendency of the 

 fresh water is checked by the advancing tide. When this is the 

 case, the first efi'ect is to cause the waters to swell, while still 

 running down, and we may likewise note that there are two 

 currents running in opposite directions, the one creeping up the 

 sides of the river, while the central current runs down, and just at 

 the turn of the tide there is still water which is thick, and at this 

 time the greatest deposit takes place. Another matter of import- 

 ance is the relative strength of the tides. Off Ramsgate the flood 

 runs N.E. about five hours and then turns West and runs down 

 seven hours, and the same is the case at the mouth of the river. 

 So when near the mouth the incoming tide has a greater carrying 

 power than the ebb, the efi'ect being that in this part of the river 

 the silt is brought up with the tide, and deposited only where the 

 effect is counterbalanced by the fresh waters coming down. At 

 Eye the Commissioners of Sewers have erected flood-gates across 

 the Eother, preventing the flood-tide coming in, the result is there 

 is a great deposit of mud seaward of the obstruction but very little 

 beyond. 



In the case of the Stour and its tributaries, according to 

 historical evidences, there had formerly been two outlets, one 

 towards the S. East near Sandwich, and other N. West near 

 Eeculver ; and when this was the case there must have been a 

 rapid deposit of silt. It would seem the effect was that the 

 Northern outlet for the Stour waters was very early stopped by 

 the silt, and the river's course henceforth must have been at the 

 sea at or near Sandwich. 



The estuary that formerly separated the Isle of Thanet from 

 the mainland of Kent, was called by tlie Venerable Bede, the 

 Wantsum, and it flowed through the marshland now constituting 

 the Levels of Ash, Minster and Chislet, or Reculver, the whole of 

 which consists of Alluvium, except some detached hills at Sarre, 

 Stourmouth, Minster, and in Ash Level. 



In early Saxon times, perhaps also in Koman times, sundry 



