220

GENERAL OBSERVATIONS ON THE STRATA.

new situation be found at ah , fig. 4, forming the short verticallines that stop against the curve in the present cliff.

It is unnecessary to consider the upper part of this arch, as ithas been entirely removed, and a new outline, cd , BE, (fig. 4.)cutting across the whole of the strata, has been substituted,forming the present surface of the land.

The idea above stated, that the small portions of vertical layerswhich meet the curved part was originally owing to a bank,was suggested to me by what I have noticed in sandstones, andin the daily effects of the tides on the sands of a shore ; where itmay be easily seen, that each successive tide displaces a part ofwhat was deposited by the former, covering it with new matterin a stratiform manner.

That many strata were at some period pliable, and capable ofbeing bent into curves, is rendered probable by the contortions Ihave described in Durlstone bay, and other places, and also b ythe various degrees of inclination of the beds of chalk itself, aswell as of the other strata, as seen in the west and east end of theIsle of Wight.

I am aware that this theory may also be applied to accountfor the appearances at Alum bay, where the northern horizontalstrata meet the vertical strata in a manner somewhat similar.The two cases, however, are not exactly alike. Besides that atAlum bay the horizontal and vertical parts are evidently of dif-ferent formations, the curve in the former is very small, not beinggreater than may perhaps be explained by deposition on thesides of a basin; and the passage from the horizontal to thevertical strata is too sudden to suppose that the bending tookplace in the interval between them. It was this circumstance,