EXPLANATION OF THE PLATES.

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of black clay with septaria, mentioned page 212, and which I have classed as one ofthe beds of the plastic clay series. This bed does not appear to be extensivelycontinuous, as 1 did not observe it in Whitecliff bay. 1 found but few fossils in it,and those not characteristic of the London clay, but rather agreeing with the Wool -wicli beds. From this to G, is a series of alternations of various substances, variouslycoloured sands, pipe clay, fuller’s earth, ferruginous sand stone, &c. The perpendi-cular part, under F, is removed some way back. Under G, is one of the coal series,between which, and the other one at I, is a bed of pure white sand in which are severalvertical layers of rounded and water-worn chalk Hints, most of which are entirelydecomposed, having become perfectly white and opaque throughout. The beds fromthis to K consist of red and white sand only. The ridge under Iv, which runs downto the beach, and which is immediately to the right of the dark stratum under L, is thatwhich contains a considerable layer of large rounded Hints also in a vertical position;they are imbedded in a sand intensely yellow. These flints are very deserving ofnotice, as they furnish the most decisive evidence respecting the original position ofthe whole of these strata. The dark stratum, under L, is the bed of black clay withgreen earth and septaria, which, from its numerous fossils, l consider as identical withthe Loudon clay. Here is the chasm where the path leads down to the beach, andwhich cuts off the distinct connection between the vertical strata and the highlycurious and interesting series of beds that appear in a horizontal position to the left.The hill extending from L to N is called Headen ; and the lowest of its strata, nextto the beach, consists of sand, of whieli a small part immediately on the north of thechasm inclines about 45°, but which becomes soon horizontal. This horizontal part isbeautifully white, and here are dug the pits from which the glass-houses are supplied.Over it is a bed of black clay without fossils. The stratum above this, which iscurved at the end, and suddenly stops at the chasm, is that which I made out to bethe lower freshwater formation, and consists of a series of thin beds of slightlyindurated sand stone, marie, &c. with numerous fragments of freshwater shells.Upou it rests the upper marine formation, consisting of a thin bed of dark greenishand black marl and clay, with vast numbers of fossil marine shells in beautiful pre-servation. The whole of the beds forming the perpendicular cliffs above this com-pose the upper freshwater formation, distinguished by its numerous and exquisitespecimens of fossil freshwater shells. These beds are unique in this country, butexactly resemble those of the basin of Paris . The greater part, if not the whole, ofihe hill above, seems to consist of Hint gra\el. The headland, under O, is part ofTotland bay, where the same strata may be seen as at Headen. At P, is Wardenpoint, the northern side of Colwell bay. Beyond, is the low coast towards Cowes.See Letter VI, and pages 211, 212.