ALUM BAY.

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The north end of these curiously coloured cliffs is terminatedhy a very thick vertical stratum of blackish clay with much greenearth, which contains septaria and a great number and variety offossil shells. These fossils I recognised to correspond with thosein the Hordwell cliff in Hampshire, on the opposite shore of theSolent, which are so well described in the publication of Branderand Dr. Solander. This circumstance is extremely interesting;as it serves to connect this stratum, though vertical, with that ofthe Hordwell cliffs, which is horizontal. In the middle of thestratum, a deep hollow is worn, through which a stream of watercomes down ; and a path leads up, and passes through a rabbitwarren.

To the north of this stratum a dirty yellow sand joins; butwhich appears not to be vertical, but rather dips about 45° to thenorth : this, however, was not very evident.

On this last sand leans a very thick bed of sand (Tl. XXIII,)which is extremely white and pure, and which is very nearlyhorizontal; it may be traced to the north, quite round Totlandbay. It is this horizontal bed of white sand, which they dig andexport to the glass houses, where it is employed for making thebest glass. Over it, is a stratum of black clay, upon which resta series of very singular strata, consisting of marl, shale, and softcalcareous stone, the whole containing numerous fossil shells,chiefly in fragments; above these, and a little removed back, arecliffs of similar horizontal strata of considerable height: andthese continue with interruptions round the north-west part ofthe island.

The lower part of this series of horizontal strata is bent upwards,and suddenly broken oil', where it comes up against the vertical