that in the upper beds, comprising a thickness of nearly 700 feet, but twenty additional species are met with; the absolute number of fossils also rapidly diminishes, but few, if any, organic remains appearing in the uppermost layers. But throughout this period of consecutive deposition, one series of fossils only is indicated, bounded by the Wealden below and the galt above. It is the lowermost part of the Atherfield section which is regarded as the equivalent of the remarkable fossiliferous group of Neufchatel. The principal difference between the continental and English greensand fauna, is stated by Professor E. Forbes to consist in the abundance of gasteropoda and cephalopoda in the former, and of acephalous bivalves in the latter.

GREENSAND FOSSILS.* The organic remains of the greensand to be met with along this coast are almost exclusively shells; but few traces of the higher orders of animals, or of plants, have hitherto been observed. It should, however, be borne in mind, that remains of land. reptiles, and trees, and plants, have been found in strata of this formation in Kent; similar relics may therefore occur in the same deposits in the Isle of Wight.†

Of the vegetable kingdom but few vestiges have been discovered. The lamina of lignite in the upper ferruginous beds, and obscure traces of fuci in some of the lower sandstones, are the only indications of the flora of this geological epoch that have come under my notice. But remains of the foliage of a fern that abounds in the

*The finest collection of the organic remains of the greensand of the Isle of Wight is, I believe, that made by Captain Ibbetson, and now exhibited in the Polytechnic Institution of London. The Geological Society has the most complete series of the shells, principally contributed by Dr. Fitton, and named by Professor Forbes. Figures of most of the species will be found in "Mineral Conchology," Dr. Fitton's "Memoir," and in the " Geological Journal," vol. i.

† See "Wonders of Geology," vol. i. p. 394.

K

Wealden (Lonchopteris Mantelli, lign. 21) were discovered by Mr. Morris in many of the strata at Atherfield; and the Messrs. Gladstone have since found several leaflets of the same species associated with trigoniæ, &c., in ironstone nodules at the foot of Shanklin Cliff. This interesting fact we shall have occasion to notice in a subsequent chapter. Of the poriferæ and corals but few species occur. Traces of bulbiform siphonia (apparently S. pyriformis, Dr. Fitton's "Memoir," Pl. XV.) are sometimes displayed on the waterworn surface of fallen blocks of sandstone. A small elegant coral, a species of astrea, is not uncommon in the Cracker's Rock at Atherfield,

The lowermost beds at Atherfield Point being very fossiliferous, the collector will have but little trouble in obtaining good specimens of the shells distributed in those strata: the perna mulleti (Pl. IV. fig. 6) may generally be extracted tolerably perfect.* From the nodular masses of the Crackers, with which the shore at low water is often thickly strewn, an abundance and variety of shells may be procured; and that part of the cliff where the two parallel layers of these concretionary masses are within reach (almost half a mile to the east of Atherfield Point), will afford specimens at all times. The large gryphea sinuata (Pl. V. fig. 3) may be found everywhere along the shore; the shell being sufficiently strong to resist for a time the action of the waves, clean and perfect examples often occur imbedded in the sand. Beneath Walpen Highcliff, and at Whale's Chine, the gryphea bed may be examined in situ; the terebratula sella (Pl. V. fig. 5) may be obtained from the loose green sand (No. 6, p. 165) in great perfection and variety.

* It is necessary that the geologist should so arrange the time of his visit to this coast as to arrive at Atherfield at the beginning of the ebb of the tide, that he may be able to examine the cliffs and collect specimens at leisure.

*

The magnificent cephalopodous shell, the Scaphites grandis (S. gigas of our Pl. V. fig. 11), is most likely to be met with near the base of the same part of the cliffs. Some fine specimens have been found along the shore near Ladder Chine; and very large ammonites and nautili occur in the same locality. On the shore, not far from the base of Blackgang Chine, nodules with scaphites may be observed above a bed of sand full of terebratulæ.

The fossil lobsters, the most beautiful of the Atherfield fossils, may generally be met with after recent slips of the cliff involving masses of the strata (Nos. 3 and 5, p. 164, 165), in which they occur. The vignette of this volume (engraved by Mr. Lee from a drawing by Mr. J. Dinkel) represents an exquisite specimen from a fallen block lying near the pathway at the foot of Atherfield Cliff.

Minute bones of fishes in the lowermost clay, and a few teeth of the shark family, are the only remains of vertebrate animals I have observed; but Captain Ibbetson has obtained from these cliffs a specimen of extraordinary interest. It is a considerable portion of the skull, with the bones of the face and the jaws and teeth attached, of a species of hybodus; a genus of fishes of the shark tribe, having teeth of a transversely elongated form, with a series of compressed conical cusps, of which the middle one is the longest.†

In this remarkable fossil the mouth is open, and forms

* The shell has been described under different names, as Crioceras Bowerbanksii, Scaphites gigas, &c.; the latter name is given in the description of Pl. V., but Professor E. Forbes has adopted that originally affixed to this gigantic cephalopod by Mr. Sowerby. Scaphites are distinguished from ammonites by the disunion of the whorls, and from hamites, by the spiral arrangement of the posterior volutions. A very small species of scaphite (not exceeding an inch in length) is frequent in the chalk marl. See "Medals of Creation," vol. ii., for an account of fossil Cephalopoda.

"Medals of Creation," vol. ii. p. 622.

a semilunar aperture six inches wide. The upper jaw has twenty-four teeth, and the lower nineteen, in their natural position; two rows of successional teeth are traceable behind the anterior series. These teeth, as shown in lign.

19, have a central cusp rather hooked, and two lesser points on each side.

LIGN. 19-FIVE TEETH ATTACHED TO A PORTION OF THE JAW OF A FISH OF THE SHARK FAMILY; FROM ATHERFIELD.

(Hybodus bassanus, of Sir P. Egerton. "Geol. Journal," vol. i. pl. iv.)

The hybodonts, like other fishes of this family, were armed with strong dorsal spines, which are often found in the lias, oolite, and Wealden strata; and, rarely, in the chalk.*

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THE CLIFFS AT BLACKGANG CHINE. -Proceeding from Atherfield Cliffs eastward, the first interesting point is Blackgang Chine; a spot well known to every tourist who visits the Undercliff. Viewed from the sea-shore at low water, especially when the springs which feed the waterfall have been swollen by heavy rains, the effect is highly picturesque. The cascade falls in a perpendicular column from a ledge 70 feet high, down the midst of a deep chasm formed in dark ferruginous clays and sands, and surmounted by broken cliffs 400 feet high; and towering above all is the majestic escarpment of Saint Cathe

• Capt. Ibbetson's specimen is in the Polytechnic Institution on a pedestal at the entrance of the Isle of Wight model-room. It is figured and described by Sir Philip Egerton in "Geol. Journal," vol. i. p. 197. Unfortunately, the drawing was made before the bones of the face and jaws were cleared of the adherent stone, and it therefore represents only the margin of the jaws with the teeth, surrounded by a shapeless mass.