§ 42. The mineral productions of the grey-marl, consist of crystallised carbonate of lime of various forms; and sulphuret of iron. A reddish oxide of iron is also very common; and sulphate of lime is occasionally met with in nodules of pyrites.

§ 43. The organic remains are numerous, particularly of the testacea; but the substance of the shells is very seldom preserved.

§ 44. The vegetable fossils resemble those of the chalk; the supposed juli are found in great perfection at Hamsey marl-pits; and wood, and impressions of leaves, are not very unfrequent.

§ 45. The Zoophytes consist of millepores, sponges, and alcyonia, but these are seldom found in a good state of preservation.

§46. The echinites are not numerous, and are generally very imperfect; a delicate and elegant species of cidaris, is the most interesting species we have discovered."

$47. Of the simple univalves, shells of the genera voluta, buccinum, rostellaria, trochus, auricula, ampullaria, and vermicularia, have been collected.

$48. The multilocular univalves are very numerous. The rare genera of turrilites, scaphites, and hamites, are found at Hamsey and other places. Of the former, three species are known, viz.: turrilites costatus, Tab. xxviii, 4. T. undulatus, Tab. xxviii.-fig. 5, represents a block of marl, to which two individuals, and an ammonite, are attached; the left hand specimen is highly interesting, since it shews the base of the columella.

T. tuberculatus, Tab. 3, occurs at Stoneham and Middleham.

§ 49. Two species of scaphites have been found at Hamsey, viz.: S. striatus, Tab. 28, fig. 1, and S. costatus, fig. 2. Of the hamites, six species occur, of which the most remarkable is H. armatus. § 50. The marl contains eight species of ammonites; three of which are represented in Tab. 28, fig. 6. Ammonites Sussexiensis; fig. 7, A. Mantelli; and fig. 8, A. varians.

§ 51. The only nautilus of the Sussex marl, is the nautilus elegans of Sowerby.

52. The bivalves, consist of various kinds of shells, of the genera ostrea, pecten, plagiostoma, inoceramus, &c., but none of these are sufficiently remarkable to require notice in this brief compendium.

§ 53. The teeth and scales of fishes, and the remains of crustacea, are neither numerous nor important in this deposit.

§ 54. BLUE MARL OR GALT.-A stiff blue clay underlies the grey-marl, and rises to the surface on the northern edge of the latter. It is provincially termed malm, or black land, and although producing a very stiff soil, constitutes a belt of land remarkable for its fertility. This bed abounds in Ammonitæ, Nautili, Belemnitæ, &c., and the specimens are generally of a most splendid description, the substance of the shells being preserved, and having its original pearly lustre, heightened by the process of mineralization.

§ 55. The mineral productions of this bed are crystallized sulphate of lime, iron pyrites, and thin layers of a reddish brown indurated marl.

§ 56. The organic remains are very numerous, and differ most essentially from those of the beds both above and below it.

§ 57. Wood of a fine texture, and susceptible of a good polish, is found in the lowermost strata, at Willingdon, and on Berwick Common; corals of a delicate form, belonging to the genus Turbinolia, have been collected at Ringmer; and small pellucid Belemnites are so abundant, as to be exposed by the plough; they are called "pencils" by the labourers. Ammonites, Nautili, Hamites, Dentalia, and shells of many other genera, are every where distributed. The Hamites are of great beauty, and some of the most perfect yet known, have been found in this bed at Cooksbridge.

§ 58. Of the Bivalves, the Inocerami, particularly I. concentricus and I. sulcatus, are the most

common.

§ 59. Several small Crustacea also exist in this deposit, but they are very rare; they belong to the genera Arcania, Corystes, Etyus, and Astacus.

Of fishes, a few teeth, scales, and vertebræ, are the only remains hitherto discovered.

Strata of Tilgate Forest.

Ashburnham beds.

60. The strata beneath the chalk formation, form three principal divisions; the arenaceous de

The

posits being divided by a thick stratum of blue clay, containing layers of shelly limestone. upper bed of sand has been termed the Green Sand; and although in many parts of its course the colour of the strata does not accord with the term employed, yet to avoid confusion we shall use it to designate the arenaceous strata above the Weald Clay, without any reference to the colours they

may assume,

§ 61. GREEN SAND.-The strata composing this formation consist of loose sand and sandstone. The sand is siliceous, but the sandstone is generally formed by a calcareous cement. Small portions of mica, and numerous particles of green chlorite of iron, are abundantly dispersed throughout the mass; and in some places, as at Ringmer, Norlington, and the Beechwood, &c., these are so numerous, as to give a green colour to the rock. In some localities the sand is white; in others of various shades of reddish brown. The town of Ditchling stands on masses of the latter variety.

§ 62. The course of this bed is but obscurely exhibited in this part of Sussex. It rises from beneath the outcrop of the blue marl, and protruded portions of it are here and there visible in a line parallel with the basseting edge of that deposit; but it is traced with considerable difficulty.

§ 63. Although in many parts of England, and in a few localities in this county, organic remains are found in this bed, yet in the vicinity of Lewes no traces of fossils exist. At Eastbourn, where the sand is intermixed with so large a proportion of calcareous and argillaceous matter, as to constitute a sandy marl, rather than a sandstone, many zoophytes, and a few shells have been discovered.

§ 64. WEALD CLAY.-The Green sand is succeeded by a tenacious clay, varying in colour from a yellowish brown to a dark bluish grey, and containing in certain parts of its course, beds of the shelly limestone, so well known by the name of Sussex marble. This deposit forms a vale of considerable breadth, occupying the lower parts of the Wealds of Kent and Sussex, and skirting the base of the chain of sand hills which forms the boundary line of the two counties. This tract of country abounds in forests of oak, and is remarkable for the badness of the roads by which it is intersected.

§ 65. The clay is destitute of organic remains, but it is characterised by the strata of shelly limestone, which occurs in various parts of its course. This limestone is so familiar to the reader by the name of Sussex marble, that a description of it is unnecessary; a small slab from Laughton is figured in Pl. xxix. 6. The Sussex marble occurs in layers, from a few inches, to a foot or more in thickness, which are separated from each other by blue clay: The compact varieties bear a good polish, and are both beautiful and durable. The cluster columns in the gate-way of the Priory, which have stood nearly five hundred years, are composed of this substance. The less perfect kinds, form good materials for the roads, and might be converted into excellent lime.

In an economical point of view, a knowledge of the situation and course of this marble, is therefore important; and this circumstance may be adduced, as one of the numerous instances of the benefits resulting to the community at large, from scientific investigations. By this knowledge an enlightened nobleman, (the Earl of Chichester), to whose public spirit, and indefatigable exertions, we are indebted for the present excellent state of the turnpike roads in Sussex, was enabled to point out to the inhabitants of Laughton, a source of profitable employment for their poor, in those seasons when agriculture no longer afforded them the means of obtaining subsistence.

§ 66. In those places that are accessible to observation, the uppermost layer of Sussex marble, lies but a few feet beneath the surface; this is separated from the next layer by blue clay, varying in thickness from six, to eleven feet; the inferior stratum of limestone, being frequently from twelve to twenty inches in thickness. In sinking a well at Plashett Park, three layers of the marble occurred in the depth of twenty-six feet.

§ 67. The course of the limestone is in a N.N.W. direction, extending from Kirdford in western Sussex, to Laughton: from whence it proceeds eastwardly, and is lost in the alluvial marshes of Pevensey levels. Wherever it approaches the surface, it occupies moderately rising ground, and frequently occurs on the north side of a rivulet. If we make allowance for the inequality of the surface of the country, and the displacement which the strata have sustained, the Sussex marble will, in all probability, be found to the north-east of a line drawn from Laughton church to the north of Hurstperpoint.

Nearly twenty localities of this marble are mentioned in the Geology of Sussex, pp. 65, 66.

§ 68. The shells that form so considerable a portion of this marble, are supposed to resemble the recent Felix vivipara, which is an inhabitant of our rivers; and they have accordingly been named by Mr. Sowerby vivipara fluviorum, but it seems doubtful if the appropriation be correct.

§ 69. IRON SAND.-This deposit which constitutes the forest ridge, and a large proportion of the north-eastern part of the county, is composed of siliceous sand and sandstone, more or less tinged by yellow and brown oxides of iron. In some parts, that mineral is so abundant, that in * d

the early centuries, when the forest of Anderida afforded a constant supply of fuel, some of the beds were worked for the ore of that metal, particularly in the eastern division of Sussex.

§ 70. The nearest approach of the iron sand towards Lewes, is at Chailey, Isfield, Little Horsted, &c., and from thence to the borders of Kent, sand and sandstone appear at the surface with but little interruption. Scarcely any tract of country is less interesting to the geologist than this, for it is destitute of organic remains and presents nothing in its mineralogical characters to engage his attention. To the admirer of the picturesque, however, it possesses charms superior to any other part of the county; for although, from the ferruginous impregnation of the soil, the more elevated portions are marked with sterility, yet here and there its wild and romantic groups of rocks, partly overgrown with lichens and crested with the beech and fir, give a character of romantic grandeur to the scene, of which the more cultivated and fertile tracts are destitute.

§ 71. In the neighbourhood of Uckfield, about half a mile to the west of the church, a group of sandstone rocks occurs, under circumstances of considerable beauty and picturesque effect. The path which leads to this interesting spot lies to the right of the road, and by a circuitous route conducts the spectator to the centre of a wood, where a beautiful lake, nearly surrounded by rocks, suddenly opens to the view. The cliffs overhanging the water, are from twenty to thirty feet high; and are surmounted by forest trees and underwood. In some places the rocks are nearly perpendicular; in others they descend with a gentle slope to the water's edge, the declivity being covered by luxuriant vegetation. On the northern margin, a projecting point of high rock, is perforated by a natural archway, which has been enlarged by art, and this leads to a recess in the sandstone, on a level with the bosom of the lake, (see the vignette); from this spot the beauty of the scene is exhibited to peculiar advantage. On the opposite shore, the base of a rock that juts into the water, is in like manner excavated into an arch, beneath which a little shallop was moored at the time of our visit. In one of the vertical cliffs, some fine young beech trees had taken root between the thin layers that separate the strata, and in almost every fissure of the rocks numerous plants had insinuated themselves, and by the beauty and variety of their foliage, relieved the monotonous and sombre appearance of the smooth grey sandstone. On the less elevated masses, lichens, mosses, and heaths, were growing in great profusion and luxuriance.

§ 72. A fine lake, overhung with sandstone rocks, and crested with a noble wood, near the seat of the Earl of Sheffield, at Fletching, may also be noticed as an example of the picturesque scenery, to which the irregular surface of this formation gives rise in certain situations.

§ 73. The only mineral substance, with the exception of the iron ore already noticed, demanding our attention, is the lignite or imperfect coal, which has been discovered in Newick Park, and some other places. This substance partakes of the characters of jet, is of a velvet black colour, does not soil the fingers, is very brittle, and burns with a bright flame. A layer of this mineral, a few inches thick, occurs in Newick Old Park, beneath several alternations of sandstone, indurated blue marl, and blue clay.

§ 74. Of organic remains, the only kind hitherto discovered in the iron sand, is a species of fern, which occurs in the sandstone at Worth;, a specimen is figured in Plate xxix. 18.

§ 75. LIMESTONE OF TILGATE FOREST.-Although but few traces of these deposits exist near Lewes, yet they constitute so important a feature in the Geology of Sussex, and the characters of their organic remains are so remarkable, that we cannot conclude this sketch without offering a few observations respecting them.

§ 76. These strata, which from the place where their characters are most distinctly developed, we have named the Tilgate beds, consist of various layers of sandstone, limestone, and calcareous slate, covered by a thick bed of diluvial aggregate; the whole reposing on blue clay of an indeterminate thickness. They rise from beneath the iron sand, but whether they are subordinate to that formation, or lie beneath it, has not been correctly ascertained. The course of these strata has been but imperfectly explored; yet there is reason to conclude that they extend through the county from Horsham to Tilgate, and from thence to Hastings; the limestone in these different localities, and some of the organic remains, being precisely similar. The same strata have been quarried at Linfield; at Chailey North-Common; and in the parish of Chiddingly.

§ 77. The organic remains of these beds consist of the casts of univalves and bivalves; of the stems of plants allied to the Euphorbic and Cacti ; the leaves of unknown species of ferns, and other vegetables, and of fruit or seed vessels: bones and plates of fresh-water, land, and marine turtles; teeth of sharks and other fishes; and the bones, scales, and teeth of a gigantic crocodile, or alligator; (a tooth of this kind is figured in Pl. xxix. 1.) Also the teeth of the Rhinoceros; bones of the elephant, and of some large unknown quadruped; and the teeth, and probably bones, of an herbivorous animal, which M. le Baron Cuvier, (who did me the honour to examine them), assures me are