146 J. S. Gardner — Oscillations of Level on 8. Coast. 



Ictis and St. Michael's Mount I do not know ; but he has not con- 

 clusively established that between b.c. 9, and now, there hns been no 

 change of level there. For a good thousand years of the time, Ictis 

 might have been a complete island or a complete peninsula, as we 

 are without records, so long as it afterwards reverted to its original 

 state ; or there might have been upheaval of the causeway counter- 

 balanced by the removing power of the waves ; or depression of the 

 causeway keeping pace with— concealed — by fresh deposits of sands. 

 The Wash is a long way to go for another example of the stability of 

 coast-land, while as for the opinions of the early English chroniclers, 

 it is not likely they would have observed movements of the coast 

 which scientific observers of the present day have not remarked upon. 

 Now let us glance along the South Coast only, and we shall find 

 the A'ery reverse of stability. To begin with the Tilbury Docks — 

 down to the very bottom they are blue clay and decayed vegetable 

 layers, the latter so fresh at 40 feet depth that they are still 

 offensive. The subsidence evidenced here can be traced to the 

 mouth of the river. The Swale at Sheppy has, on the other hand, 

 I believe, risen. The Eeculvers have risen — the bed of the river 

 which once formed the Isle of Thanet is in places, I believe, above 

 the sea-level. The coast off Eichborough has greatly risen since 

 Eoman times. I have not observed the chalk clifi-lines since I 

 became interested in the subject, but the Hythe coast must have 

 risen quite 30 feet since Eoman times, and the Dungeness shingles 

 are much too high to have been piled in their present position by 

 the sea. The Pevensey flats must also have risen. The sea front 

 of Kent thus seems to be rising, Sussex is .partly rising, partly 

 sinking. The sudden irruption of sea and loss of 2700 acres at 

 Selsea indicates subsidence. At Pagham Harbour there is evidence 

 of elevation, first> a long continued period of terrestrial surface, and 

 finally subsidence followed by the accumulation of estuarine mud. 

 Eecent changes of level are indicated in the Solent by the steep fronts 

 of the mud flats, destitute of weed, which are seen at low-water, 

 proving that a wasting action has set in. The disappearance of 

 mud flats on its shores, described by Fielding in 1753, is evidence of 

 depression during this century, and I have even myself noticed a very 

 great diminution in the mud off Eyde within the last thirty years. 

 Stumps of trees under mud and shingle show a depression of 40 to 

 50 feet. East of the mouth of Beaulieu river there is a broad 

 expanse of shingle above highest tide, partly overgrown and over- 

 looked by vertical cliffs which the sea never reaches. There are 

 slight evidences of depression in Brading Harbour, amongst others 

 a well has been rendered useless through being covered by the sea 

 at high tide. A well at Portsmouth revealed stumps of trees 

 29 feet below high-water mark, among them Lacuna Montagnei and 

 Zostera marina on which it fed, indicating very shallow salt water, 

 above which is 4 feet of blue clay with common living shells. 

 Part of Fort Cumberland, near Portsmouth, stands on a bank of 

 gravel and sand, and owing to some new groins, a fresh direction 

 was given to the tide and a portion of the bank washed away, in the 



