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bay by a ledge of rocks which extends out some distance beyond low water.
At the east end of the bay, at Brook Point, the cliff consists of the Wealden strata at the base, above which is pale grey sandstone and red and green marls.
In Brook Bay lignite and iron pyrites are found on the beach, the cliffs consisting of red and yellow sands. Brixton Bay is bordered by cliffs of grey shale, with beds of limestone and sandstone. At Atherfield the cliffs, which are 150 feet high, consist of greensand and Wealden clay; and a ledge of rock extends out from the shore for some distance below low water. The cliffs along this part of the coast belong to the Punfield series, and are similar to those exposed at Swanage.
Along all these cliffs are gaps and deep valleys known as “chines,” by which access can be obtained from the top of the downs to the beach.
West of Blackgang Chine the cliffs consist of greensand resting on gault; the face is continually sliding down owing to land-springs. The cliffs on the east side are of chalk.
The shingle in Chale Bay, at the foot of Blackgang Chine, consists of small reddish-brown rounded pebbles about half an inch in diameter, which is confined to the bay, and prevented from drifting eastward by the rocky projections at the east end. This shingle is banked up against the cliff in the centre of the bay above the level of ordinary spring tides for a width of about 50 yards, when it slopes down to a sandy beach at an angle of 1 in 2, the total width of the beach being from 70 to 100 yards. The small size of these pebbles is probably accounted for by the fact that the stones deposited at some remote period in the bay, not being able to drift out of it, have been rolled about continually by the waves and have been worn down to the present dimensions. The pebbles have originally been derived from land gravel, and not from the chalk cliffs.
Beyond Blackgang commences the great landslip which occurred about 120 years ago, and constitutes what is known as the “undercliff,” and this extends for nearly 8 miles to Luccombe. Along this stretch of coast the cliff is in terraces from a quarter to half a mile in width, about 50 to 100 feet above the sea, surmounted by a steep cliff of chalk or sandstone rising almost vertically in places to a height varying from 500 feet at Niton to 100 feet at St. Lawrence and 400 feet at Luccombe. The
highest point of the downs at St. Catherine's Point rises to 780 feet above sea-level.
East of St. Catherine's Point to Luccombe the base of the cliffs is composed of the gault clay, or “blue slipper,” as it is locally termed, and known on the south-east coast as “platimore.” The wet, filtering down on to this from the porous strata above, caused the large subsidence of the upper greensand or “firestone” rock, and chalk with flints, which rested on the gault, forming the undercliff. :
The landslips of which there are records are those of 1799, when a farm called Pitland near Niton, containing 100 acres, subsided; in 1810 there was another fall, when 30 acres subsided; in 1818, 50 acres fell, and there was a large fall in 1847.
Between Rocken End and St. Catherine's Point there is very little beach, large boulders lying at the foot of the cliffs.
The shore in Ventnor Bay has been protected by a sea-wall, against which is banked up small round red-brown shingle of a similar kind to that already described in Chale Bay, beyond which is hard firm sand.
Under normal conditions the shingle is within 4 feet of the top of the sea-wall, but in heavy south-west gales it is dragged down from 5 to 6 feet.
It is stated that previous to the year 1825 there was no shingle on this beach, but during a heavy gale the ledge of rocks to the west, at Rocken End, became broken up and lowered, allowing a portion of the shingle to drift from Chale Bay. The quantity of shingle tends to decrease, there being no fresh source of supply, any material dragged down in heavy gales and drifted along the beach to the east never returning.
Four low wooden groynes, consisting of 10-inch piles and 4-inch planking, and a stone groyne at the east end placed at right angles to the wall to prevent the shingle drifting away, were erected about thirty years ago.
To the north-east of Ventnor the beach is rocky, with small patches of shingle in the bays and indents.
In the bay at Bonchurch, three-quarters of a mile to the northeast, a sea-wall has been constructed to protect the road at the foot of the cliff, and against this is a bank 15 to 20 yards wide of large rounded black flints derived from the chalk cliffs to the west, their size varying from 1 to 3 inches, and below this shingle is firm hard sand.
Several stone groynes have been erected here for the purpose of retaining the shingle and preventing its drifting away to the north.
Between Dunnose Point and Luccombe the cliffs consist of greensand and gault, and there have been very considerable landslips. Beyond Luccombe to Shanklin the cliffs, from 250 to 330 feet high, are composed of greensand and beds of the Wealden clays.
Round Sandown Bay the cliffs at the west end are of the lower greensand formation, and are nearly vertical, the lower beds consisting of black gritty ferruginous sandstone full of dark water worn-pebbles, with quartz and jasper and concretions of iron sand.
Up to about Luccombe the shore at the foot of the cliffs is covered with large boulders. At the Chine begins a sand beach, which extends along to the coast beyond Sandown. Close under the cliff are boulders and patches of shingle consisting of reddishbrown gravel, some of the flints being stained on the surface a deep red by the oxide of iron contained in the land springs. There are also to be found remains of wood hardened by iron, and it is on this beach the chalk flints are found which are polished and sold by the lapidaries as “moss agates," and sometimes called petrified sea-anemones. The beautiful colour of these is derived from stains due to contact with peroxide of iron. The crystallized cavities in these stones contain the remains of silicified sponges, “choanites” and “ventriculites.” These cavities are sometimes lined with quartz or chalcedony. Small pebbles of pure quartz or rock crystal are also found, which, when polished, are sold as “Isle of Wight diamonds.” Mr. Mark Norman considers that these have been washed out of the Wealden strata, as identical pebbles occur in the strata at Tilgate Forest and Tunbridge Wells.
The drift of the beach along Sandown Bay is northerly, but it is stopped by the projection at Culver Cliff, at the northeast end, the foot of which projects some distance and beyond low water.
For some time past the cliffs have been giving way, and there have been some heavy falls on to the beach, partly due to land
1 “Popular Guide to the Geology of the Isle of Wight.” By Mark W. Norman. Knight. Ventnor, 1887.
Mantell's “ Geological Excursion round the Isle of Wight.” 1851.
springs, but principally from the action of the sea, which reaches the base of them at high water, the path between Sbanklin and Sandown being rendered unsafe. The beach also has become much denuded, the tide reaching the foot of the sea-wall and promenade that was built about thirty years ago. Some small groynes have been put down from time to time, but these have not been effective.
Recently application was made to the Local Government Board by the Shanklin Urban District Council for permission to borrow £2000 for the construction of two groynes for the protection of the beach and the cliffs, one to be placed at the end of the esplanade wall, 95 yards long, and the other at the north end, 100 yards long. The tender for these groynes, constructed of concrete with facing blocks, was £2200.
From Sandown the cliffs rise to Culver, the west side of which is composed of red clay, and the east side chalk. Whitecliffe Bay is bordered by plastic clay cliffs resting on chalk, capped by beds of sand and gravel, with layers of pebbles of the Woolwich and Reading series.
From the foreland at the eastern extremity of the island to Bembridge the coast is fringed by an unbroken rocky shelf, which uncovers at low water for about one-third of a mile from the shore.
North-east of Bembridge two sand-hills, which are from 10 to 20 feet in height, project out from the shore in a northerly direction for about three-quarters of a mile, and between these is the entrance to Brading Harbour and the outflow of the river. Six hundred acres of land have been reclaimed by a bank made across the estuary of the river.
The beach north of Brading Harbour is strewn with rocks, and there is little or no shingle except in patches.
The coast is wasting considerably near St. Helen's Priory.
Beyond Brading the cliffs, consisting of marls and clays and sandstone, rise to a height of 100 feet, but drop down again to about 20 feet at Nettlestone Point; the beach being of limestone rock. Westward of this, and extending for 3 miles and past Ryde, is a large area of sands, which at the widest part uncover at low water for a distance of 1.2 miles.
On the north-east side of the island, where a great deal of erosion is taking place, some groynes have been erected between Nettlestone Point and Sea View for the protection of the sea-wall there; also at North Nodes Point. Some of these are stone, and others of wood.
A wall was built along the cliffs north of St. Helen's Church, which stopped the erosion of the cliffs.
At Cowes, on the beach on the west side of the river Medina, a concrete wall and promenade extend for about 300 yards, beyond which the roadway is protected by timber breasting. Westward of Egypt Point, a new concrete wall with promenade, about one-third of a mile long, was erected by the West Cowes Local Board in 1894.
The beach is covered with shingle for a width of from 25 to 30 yards, which reaches nearly to the top of the timber breasting. The shingle is generally brown in colour, with several red flints, and has been derived from land gravel from the deposits on the top of the cliffs to the west. It varies in size from inch to 3 inches in diameter. There is a good deal of shell sand mixed with, and extending beyond, the shingle. At low-water level the beach is covered with large boulders.
The cliffs on the north-western side of the island consist of marl and clay, which in places rise to a height of 200 feet, and the shore is indented by shallow bays.
Near Hampstead the cliffs consist of green and brown mar] and clay, capped with beds of gravel.
The drift of the shingle along this part of the coast is from west to east, the same as that of the flood tide.
In the neighbourhood of Yarmouth the land is low, being not more than 10 or 12 feet above ordinary high water. Iron ore and cement stone have been dredged up from the sea-bed at this part of the coast.
The floor of the beach consists of gault, or “platner,” as it is locally called; boulders of ironstone are scattered about, and there is a small quantity of shingle. Some low groynes have recently been erected for the purpose of collecting the shingle which drifts from the west.
Near Hampstead is the largest accumulation of shingle between the Needles and Cowes, which is known as the Duvver. It is about a quarter of a mile long. At Bouldnor groynes have been erected for the protection of the frontage, and sand and shingle have accumulated on the windward or west side.
Selsea Bill and the South Foreland.—Between these points the destruction of cliffs and the waste of land have been very great,