Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/200

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Mr. Webster on the Strata lying over the Chalk.

water was then found. Another well was dug about a quarter of a mile north from Portsmouth, where water of a good quality was obtained at a depth of 126 feet from the surface. Two years ago a well was sunk in the town of Portsmouth, to the depth of 266 feet, without getting through the blue clay, and they left of without finding water. This is the greatest depth they have gone to in this place. The fossils dug up from these wells agree exactly with those found in other parts of the same stratum.”

I traced this blue clay west of Portsmouth by Emsworth and Chichester harbours to Brackelsham; and thence round Selsey Bill to Pagham harbour.

At Bognor it assumes a new character; instead of a blue clay, we find here a number of rocks, now appearing as detached masses in the sea, though evidently forming portions of a stratum once continuous. The lowest part of these rocks is a dark grey limestone, or perhaps rather a sandstone, containing much calcareous matter, enclosing many fossils belonging to the blue clay. The upper part is a siliceous sandstone. Bognor rocks resemble much the nodules and beds of limestone that are found in the blue clay in Alum bay, and no doubt are owing to the great abundance of calcareous matter in this part of the bed.

The Barns rocks between Selsea and Bognor, the Houndgate and Street rocks on the west, and Mixen rocks to the south, of Selsea, are portions of the same bed; and I found similar but smaller masses at Stubbington.

From this place to Brighton the shore is quite flat, and the chalk lies at no great depth.

The coast at Brighton has been already mentioned. At Rottendean the cliff towards the sea consists of chalk, and this continues to Newhaven. At this place a series of beds above the chalk occurs,