Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/222

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Mr. Webster on the Strata lying over the Chalk.

The section of the strata is as follows, beginning at the bottom.

1. Blue clay depth unknown
2. Sand 50 0
3. A Siliceous limestone called rag 0 6
4. Sand 0 8
5. Siliceous limestone 0 6
6. White shell-marl 0 10
7. Siliceous limestone 1 6
8. Limestone composed of the fragments of freshwater shells 1 6
9. Ditto, the fragments more apparent 2 0
10. Ditto, the fragments still larger 4 0
11. Ditto, fragments still coarser 2 0
12. Blue Clay, in which are many large and loose masses which appear to belong to the upper Freshwater formation.

At East Cowes Lord Henry Seymour had the goodness to point out to me a quarry which he had caused to be opened in his grounds, the strata of which were almost exactly the same as those of Binstead. The rag from this quarry his Lordship had employed in the construction of his mansion; and also in the fine wall which he has built to keep off the encroachments of the sea.

In the strata of East Cowes the casts of the shells are frequently entire, and appear to belong to the genus Cyclostoma Lam.

The fragment stone of Binstead, when examined with a magnifier, has a very singular appearance. In some specimens the fragments themselves remain, though in a sparry state; but in general the substance of the shell has disappeared, leaving a cavity where it formerly existed; so that in fact, instead of being fragments cemented together by calcareous spar, the stone consists of the hollow moulds of fragments held together by that matter. It would seem as if the shells themselves had been gradually absorbed into the substance of the cement.