THE SCENERY OF THE ISLAND--Conclusion.
After studying the various geological formations that enter into the
composition of the Isle of Wight, and learning how the Island was
made, it will be interesting to take a general view of the scenery,
and see how its varied character is due to the nature of its geology.
It would hardly be possible to find anywhere an area so small as this
little Island with such a variety of geological formations. The result
is a remarkable variety in the scenery.
The main feature of the Island is the range of chalk downs running
east and west, and terminating in the bold cliffs of white chalk at
Freshwater and the Culvers. Here we have vertical cliffs of great
height, their white softened to grey by weathering and the soft haze
through which they are often seen. In striking contrast of colour are
the Red Cliff of Lower Greensand adjoining the Culvers, and the
many-coloured sands of Alum Bay joining on to the chalk of Freshwater.
The summits of the chalk downs have a characteristic softly rounded
form, and the chalk is covered with close short herbage suited to the
sheep which frequently dot the green surface. Where sheets of flint
gravel cap the downs, as on St. Boniface, they are covered by furze
and heather, producing a charming variation from the smooth turf where
the surface is chalk. The Lower Greensand forms most of the undulating
country between the two ranges of downs; while the Upper Greensand,
though occupying a smaller area, produces one of the most conspicuous
features of the scenery--the walls of escarpment that form the inland
cliffs between Shanklin and Wroxall, Gat Cliff above Appuldurcombe,
the fine wall of Gore Cliff above Rocken End, and the line of cliffs
above the Undercliff. To the Gault Clay is due the formation of the
Undercliff--the terrace of tumbled strata running for miles well above
the sea, but sheltered by an upper cliff on the north, and in parts
overgrown with picturesque woods. The impervious Gault clay throws out
springs around the downs, which form the headwaters of the various
Island streams. The upper division of the Lower Greensand, the
Sandrock, forms picturesque undulating foothills, often wooded, as at
Apsecastle, and at Appuldurcombe and Godshill Park. On a spur of the
Sandrock stands Godshill Church, a landmark visible for miles around.
At Atherfield we have a fine line of cliffs of Lower Greensand, while
the Wealden Strata on to Brook form lower and softer cliffs.
To the north of the central downs the Tertiary sands and clays, often
covered by Plateau gravel, form an extended slope towards the Solent
shore, much of it well wooded, and presenting a charming landscape
seen from the tops of the downs. This slope of Tertiary strata is
deeply cut into by streams, which form ravines and picturesque creeks,
as Wootton Creek, 200 feet below the level of the surrounding country.
While much of the Island coast is a line of vertical cliff, the
northern shores are of gentler aspect, wooded slopes reaching to the
water's edge, or meadow land sloping gradually to the sea level.
Opposite the mouths of streams are banks of shingle and sand dunes,
forming the spits locally known as "dovers." Some of these, in
particular, St. Helen's Spit, afford interesting hunting grounds for
the botanist.
The great variety of soil and situation renders the Isle of Wight a
place of interest to the botanist. We have the plants of chalk downs,
of the sea cliff and shore, of the woods and meadows, of lane and
hedgerow, and of the marshes. The old villages of the Island, often
occupying very picturesque situations--as Godshill on a spur of the
southern downs, Newchurch on a bluff overlooking the Yar valley,
Shorwell nestling among trees in a south-looking hollow of the downs,
Brighstone with its old church cottages and farmhouses among trees and
meadows between down and sea--the old and interesting churches, the
thatched cottages, the old manor houses of Elizabethan or Jacobean
date, now mostly farm houses, for which the Island is famous, add to
the varied natural beauty.
One of the most characteristic features of the southern coasts of the
Island, should be mentioned, the Chines,--narrow ravines which cut
inland from the coast through the sandstone and clays of the Greensand
and Wealden strata, and along the beds of which small streams flow to
the sea. Narrow and steep-sided,--the name by which they are called is
akin to _chink_--they are in striking contrast to the more open
valleys of the streams which flow into the Solent on the north shore
of the Island. The most beautiful is Shanklin Chine. The cliff at the
mouth of the chine, just inside which stands a picturesque fisherman's
cottage with thatched roof, is 100 ft. high; and the chasm runs inland
for 350 yds., to where a very reduced cascade (for the water thrown
out of the Upper Greensand by the Gault clay is tapped at its source
for the town supply) falls vertically over a ledge produced by hard
ferruginous beds of the Greensand. Above the cascade the ravine runs
on, but much shallower, for some 900 yards. The lower ravine has much
beauty, tall trees rising up the sides, and overshadowing the chasm,
the banks thickly clothed with large ferns and other verdure. Much
wilder are the chines on the south-west of the Island. The cascade at
Blackgang falls over hard ferruginous beds (to which the beds over
which Shanklin cascade falls--though on a smaller scale--probably
correspond). The chine above these beds, being hollowed out in the
soft clays and sands of the Sandrock series, is much more open. Whale
Chine is a long winding ravine between steep walls, the stream at the
bottom making its way through blocks of fallen strata.
The cause of these chines seems to be the same in all cases. It may be
noticed that Shanklin and Luccombe chines are cut in the floors of
open combes,--wide valleys with gently sloping floors; and at each
side of these chines is to be seen the gravel spread over the floor of
the old valley. It can scarcely be doubted that these combes are the
heads of the valleys of the old streams, which flowed down a gradual
slope till they joined the old branch (or, rather the old main
river)[21] of the Yar, flowing over land extending far over what is now
Sandown Bay. When the sea encroached, and cut into the course of this
old river, and on till it made a section of what had been the left
slope of the valley, the old tributaries of the Yar now fell over a
line of cliff into the sea. They thus gained new erosive power, and
cut back at a much greater rate new and deeper channels; with the
result that narrow trenches were cut in the floors of the old gently
sloping valleys. The chines on the S.W. coast are to be explained in a
similar way. They have been cut back with vertical sides, because the
encroachment of the sea caused the streams to flow over cliffs, and so
gave then power to cut back ravines at so fast a rate that the
weathering down of the sides could not keep pace with it. The
remarkable wind-erosion of these bare south-westerly cliffs by a sort
of sand-blast driven before the gales to which that stretch of coast
is exposed has already been referred to.
A few words in conclusion to the reader. I have tried to show you
something of the interest and wonder of the story written in the
rocks. We have seen something of the world's making, and of the many
and varied forms of life which have succeeded each other on its
surface. We have had a glimpse of great and deep problems suggested,
which are gradually receiving an answer. Geology has the advantage
that it can be studied by all who take walks in the country, and
especially by those who visit any part of the sea coast, without the
need of elaborate and costly scientific instruments and apparatus. Any
country walk will suggest problems for solution. I have tried to lead
you to observe nature accurately, to think for yourselves, to draw
your own conclusions. I have shown you how to try to solve the
questions of geology by looking around you at what is taking place
to-day, and by applying this knowledge to explain the records which
have reached us of what has happened in the past. You are not asked to
accept the facts of the geological story on the word of the writer, or
on the authority of others, but to think for yourselves, to learn to
weigh evidence, to seek only to find out the truth, whether it be
geology you are studying or any other subject, and to follow the truth
whithersoever it leads.
[Footnote 21: See p. 91.]
TABLE OF STRATA
Recent. Peat and River Alluvium.
Pleistocene. Plateau Gravels: Valley Gravels and Brick-Earth.
{ Pliocene} Absent from the Isle of Wight.
{ Miocene }
{ { { Marine, Corbula Beds
{ { Hamstead { Freshwater & Estuarine.
{ {
{ { { Bembridge Marls
{ { Bembridge {
{ { Beds { Bembridge Limestone
{ {
{ Oligocene { Osborne and St. Helen's Beds.
{ {
Tertiary { { { Upper. Freshwater and Brackish
{ { Headon { Middle. Marine
{ { Beds { Lower. Freshwater and Brackish
{
{ { Barton} Barton Sand.
{ { Beds} Barton Clay.
{ {
{ Eocene { Bracklesham Beds.
{ { Bagshot Sands
{ { London Clay
{ { Plastic Clay (Reading Beds)
{ { White { Upper Chalk (Chalk with flints)
{ { Chalk { Middle Chalk (Chalk
{ { { without flints)
{ {
{ { { A. plenus Marls
{ Upper { Lower { Grey Chalk
{ Cretaceous { Chalk { Chalk Marl
{ { { Chloritic Marl
{ {
{ { { Upper { Chert Beds
{ { Selbornian { Greensand { Sandstone and
{ { { Rag Beds
Mesozoic { { Gault
or {
Secondary{ { Carstone
{ { Lower { Sandrock and Clays
{ { Greensand { Ferruginious Sands
{ { { Atherfield Clay
{ Lower { { Perna Bed
{ Cretaceous {
{ { { Shales
{ { Wealden { Variegated Marls
FOR FURTHER STUDY.
Memoirs of the Geological Survey. General Memoir of the Isle of Wight,
date 1889. New edition, entitled "A short account of the Geology of
the Isle of Wight," by H. J. Osborne White, F.G.S., 1921, price 10s.
The Memoirs are the great authority for the Geology of the Island:
technical; books for Geologists. The New Edition is more condensed
than the original, but contains much later research. Mantell's
"Geological Excursions round the Isle of Wight," 1847. By one of the
great early geologists. Long out of print, but worth getting, if it
can be picked up second-hand.
Norman's "Guide to the Geology of the Isle of Wight," 1887, still to
be obtained of Booksellers in the Island. Gives details of strata,
and lists of fossils, with pencil drawings of fossils.
Other books bearing on the subject have been mentioned in the text and
foot-notes.
An excellent geological map of the Island, printed in colour, scale
1 in. to the mile, full of geological information, is published by the
Survey at 3s.
A good collection of fossils and specimens of rocks from the various
strata of the Isle of Wight has recently been arranged at the Sandown
Free Library, and should be visited by all interested in the Geology
of the Island. It should prove a most valuable aid to all who take up
the study, and a great assistance in identifying any specimens they
may themselves find.
[Illustration]
GEOLOGICAL MAP OF THE ISLE OF WIGHT
INDEX
Words in Italics refer to a page where the meaning of a
term is given.
Agates, 22, 41, 50
Alum Bay, 56-62
Ammonites, 32, 34, 39, 44
_Anticline_, 12
Astronomical Theory of Ice Age, 83, 85
Atherfeld, 29
Avon River, 94
Barrows, 102, 104
Barton, 61
Belemnites, 33
Bembridge Limestone, 65
-- shingle at, 95
Benettites, 27
"Blue Slipper," 15
Bonchurch, 50, 103
Bos primigenius, 101, 102
Botany, 106
Bracklesham, 59, 60
Brading Harbour, 90, 91
Bronze age, 103
Brook, 29
Building Stone, 39, 65
Carstone, 26, 35
Chalcedony, 22, 41, 50
Chale, 33
Chalk, divisions of, 45, 51, 52
-- Marl, 45
-- Rock, 45
Chalybeate Springs, 25
Chert, 39
Chloritic Marl, 44
Climate.
Coal, 8, 61
Colwell Bay, 64
Compton Bay, 31, 39
Conglomerate, modern, 25
"Crackers," 32
Cretaceous.
Crioceras, 34
Current Bedding, 27
Cycads.
Denudation, 3, 12, 76, 80, 82
_Dip_, 11
Echinoderms, 48, 52
Eocene, 54
Erosion, marine, 4
" pre-Tertiary, 54
_Escarpment_, 14
_Faults_, 13
Fault at Brook, 30
Flint, origin of, 47
" implements, 97
Flora, Alum Bay, 59
" Eocene, 58, 62
" Wealden, 18, 27
Foraminifera, 42, 61
Gat Cliff, 38
Gault, 37
Glacial Period, 77-85
Glauconite, 24, 39, 44
Gore Cliff, 39, 44
Greensand, Lower, 23-36
" Upper, 37
Gravels, 50, 79, 89, 93-95
Hamstead, 65, 67
Headon Hill, 62-64
Hempstead, see Hamstead.
Hyopotamus, 69
Ice Age, 77-85
Iguanodon, 20
Insect Limestone, 67
Iron Ore, 22, 24
Iron pyrites, 22
Landslips, 25, 38
Limnaea, 63, 64, 66
Lobsters, Atherfield, 32
London Clay, 57
Luccombe, Landslip at, 25
Mammalian Remains, 66, 69
Mammoth, 77, 81
Marvel, 35
Medina, 93
Melbourn Rock, 45
Miocene, 69, 71, 76
Nautilus, 32, 45
Needles, 4
Neolithic Man, 100
Newtown River, 102
Nummulites, 61
Oligocene, 63
Palaeolithic Man, 97
Perna Bed, 23, 31
Pine Raft, 29
Planorbis, 63, 64, 66
Plastic Clay, 57
Priory Bay, 99
Purbeck Marble, 16
Quarr, 65
Rag, 38
Rock (place), 35
Roman Villas, 104
St. Boniface Down, 50, 100, 105
St. George's Down, 79, 100
Sandown Anticline, 11-13, 89
Sandrock, 25, 35
Scaphites, 34
Scenery, 105
Sea Urchins, 48, 52,
Shanklin Chine, 107
Solent, 94
Southampton Dock, 101
" Water, 94
Sponges in Flint, 47
Stone Age, 97
Strata, Table of, 110, 111
_Strike_, 11
Submerged Forest, 101
Swanage, 93
_Syncline_, 12
Table of Strata, 110, 111
Tertiary, 54
Totland Bay, 63, 95
Tufa, 45
Turtle, 58, 65, 68
Undercliff, formation of, 25, 38
Volcanic Action, 5
Wealden, 15
Whitcliff Bay, 56-67
Wood, Fossil, 8, 15, 18, 27, 29
Yar, Eastern, 89-91
" Western, 92
Zones of Chalk, 51, 52
_Printed by The Crypt House Press, Bell Lane, Gloucester._
Transcriber's Notes
With the exception of the changes noted below, the text in this file
is the same as that in the original printed version. These may include
alternate spelling from what may be common today (for example,
gneisse); punctuational and/or grammatical nuances. Additionally,
several missing periods were inserted; but are not listed below.
Lastly, the Index seems to be missing a few references to page numbers
and were left as originally printed.
Emphasis Encoding
_Text_ - Italicized Text
$Text$ - Greek translation
Typographical Corrections
Page 69: regious => regions
Page 101: sourrounding => surrounding
Page 102: remains In the peat => ... in ...
Page 106: surounding => surrounding