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the Wealden, which constitutes the axis of this line of coast.

Along the middle of the bay opposite the Fort the subsoil, except after very heavy tides, is concealed by a thick bed of shingle.*

RED CLIFF.-On proceeding eastward a low bank appears, and the coast gradually rises to the lofty hills of Red Cliff. The strata first accessible to observation are the ferruginous sands and mottled clays belonging to the Wealden formation, which become more developed as we advance towards the chalk strata that terminate in the bold promontory of Culver, which forms a striking object from this part of the bay. In the shingle may be found rolled blocks and pebbles of the Wealden shelly limestones; and of jasper and quartz, with rolled silicified zoophytes that have been washed out of the chalk.

In the Wealden, bones of large reptiles, and fruits of coniferous plants, have from time to time been discovered; and many colossal bones of the Iguanodon have been obtained from the shingle. Slabs of the paludina-limestone (see Pl. VI. fig. 3), commonly called Sussex marble, and of indurated shale full of fresh-water bivalves (Pl. VI. fig. 4), may generally be seen protruding from the clay. Masses of lignite that have fallen out of the cliffs are often found on the beach, and sometimes pebbles of silicified wood. A few hundred yards before we reach the chalk strata, laminated clay and shale appear in the

* In the section, for the sake of perspicuity, the Wealden strata in the middle of the bay are represented more lofty than they actually appear; for, in general, the sea-beach extends over the whole surface. But after sweeping spring tides in the early months of the year, the clay and sands are exposed as here represented.

In a late visit to this spot (August, 1846) a layer of Sussex marble, having a band of fibrous calc-spar, an inch thick above and below, was exposed in the clay near the base of the cliff.

face of the cliff, and the surfaces of most of the laminæ are studded with myriads of the cases of minute freshwater crustaceans, termed cyprides (see lign. 25), belonging to two or three species which are peculiar to the Wealden deposits.

It is only after recent slips of the cliffs from the inroads of the sea, that the beds are clearly exposed, and after heavy rains, that the fossil bones are brought to view by the washing away of the clay in which they are imbedded; but at all times instructive specimens of the strata, and of the usual species of shells, may be obtained. The greensand and galt are not so prolific in fossils as in some other localities; but the marl and firestone contain many organic remains characteristic of those beds.

BONES OF THE IGUANODON, &c.-The occurrence in this locality of bones of the Iguanodon and other reptiles whose remains had previously been observed only in the strata of Tilgate Forest, was first made known in 1829 by the present Dean of Westminster, Dr. Buckland. An enormous toe-bone (metatarsal), weighing six pounds, and measuring six inches in length, and sixteen inches in circumference at its largest extremity, was found in the ledges of ferruginous sand, a little to the east of Sandown Fort.* A considerable number of bones, comprising several gigantic vertebræ, portions of a femur or thigh-bone, fragments of ribs, &c., were discovered near the same spot, at the foot of the low cliff that forms the sea boundary of Yaverland farm. They were observed on the shore after a week of very stormy weather, which had swept away the beach and sand to the depth of two feet, and thus laid bare the fossils, which probably had fallen from the cliffs long previously, and being very heavy, had sunk deep into

* "Geol. Trans." vol. iii. p. 425.

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the shingle, and lain concealed till brought to light by the denuding effects of the storm. In the adjacent cliff of grey sandstone interspersed with clay, several cones of a plant allied to the Zamia, mixed with fragments of lignite, have been discovered.*

We now return to Ryde that we may proceed to the north-western part of the Island, and examine the eocene strata at Alum Bay and Headon Hill.

* One of these fossil fruits is figured and described in "British Fossil Flora," under the name of Zamia crassa; and in "Medals of Creation," vol. i. p. 160.

FROM RYDE TO

CHAPTER V.

NEWPORT-THE RIVER

MEDINA-NEWFORT TO

CALBOURNE AND ALUM BAY-THE COAST FROM RYDE TO ALUM BAY-HEADON HILL AND ALUM BAY-GEOLOGY OF HEADON HILL AND ALUM BAY-SEQUENCE OF GEOLOGICAL CHANGESORGANIC REMAINS YARMOUTH AND LYMINGTON-CHRISTCHURCH BAY-STRATA OF HORDWELL CLIFFS-HORDWELL FOSSILS.

FROM RYDE, THROUGH NEWPORT, TO ALUM Bay.—From Ryde, the journey to Alum Bay may be performed either by land or sea. The road passes by Binstead, and through the picturesque village of Wootton-bridge, to Newport, the capital of the Island. In the rooms of the Newport Institution, there is a miscellaneous collection of organic remains; but it is much to be regretted that a complete series of specimens, illustrative of the geology of the Isle of Wight, is not to be met with in this or any other town in the Island.

Newport is situated on freshwater eocene strata, which are a continuation of those of Headon Hill, and lie in a nearly horizontal position; the wells in the town are sunk through these beds, to the depth of 200 feet. At Parkhurst barracks a well was dug through 300 feet of London clay, containing a few thin seams of shells. On examining the nature of the soil in the tract between the town and the neighbouring chalk hills, the vertical* marine strata are

* Mr. Webster notices a clay-pit, opened for a brick manufactory, in which were clay and sand strata in a nearly vertical position, and the upper portions contorted as if from pressure. Sir H. Englefield's "Isle of Wight," Pl. XXXIV. fig. 1.

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found occupying the same relative position as at Whitecliff Bay. In a heap of clay that had recently been dug up from the bottom of a well, Mr. Webster discovered vestiges of coleopterous insects; and obtained several fossil seedvessels of a plant related to the Meadow-rue (Thalictrum); they consisted of the pericarp, in a carbonised state, filled with clay.*

The quarries in the neighbouring chalk down of Mountjoy, to the southward of the town, expose some interesting sections of the highly-inclined strata of chalk and flint; and the summit of the hill commands a most extensive and delightful prospect.

RIVER MEDINA.-The Medina river, which rises at the foot of St. Catherine's Down, and divides the island into two nearly equal portions, called the East and West Medina, flows through a transverse valley of the chalk range on the south, and winding round the east end of the town, becomes navigable for vessels of considerable burthen, to its entrance into the sea at Cowes. The valley of the Medina, like the river valleys of the North and South Downs,† is a transverse dislocation, or rent, across the range of chalk hills, produced by the tension of the strata during their elevation from the horizontal to their present nearly vertical position.

The transverse course of the Medina through the middle of the central ridge of chalk, is noticed by Mr. Hopkins in his memoir "On the Geological Structure of the Wealden District, and of the Bas Boulonnais," with the accompanying diagram, lign. 10, which represents an east and west section of the valley near Rookley, about four miles

* A figure of this fruit (which has been named by M. Adolphe Brongniart, Thalictroides Websteri,) is given in the "Medals of Creation," vol. i. p. 190.

"Geology of the South-east of England," p. 350.
"Geol. Trans." vol. vii. p. 24.

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