Page:Quarterly Journal of the Geological Society of London, vol. 31.djvu/79

Rh IN THE ISLE OF PORTLAND AND AROUND WEYMOUTH. 33 trace of this interesting deposit in any other of the quarries or sections of the island. The Purbeck beds everywhere present a bare and broken surface. The Raised Beach (e, Map and Sections, PL I.). This beach extends on the east side of the Bill, exactly one mile from the Sand-holes near Southwell to the " land-mark " at the Bill, and appears to range about a furlong inland, passing under a covering of sand, loam, and rock-debris. From the Bill it extends along the west cliff for a distance of about a quarter of a mile, when it ends against an old subsoil cliff. This old beach is most largely developed and thickest on the west side of the Bill ; but it there scarcely contains a shell. It is a mass of well worn and rounded shingle from 5 to 10 feet thick. On the east side, where the coast recedes and was more sheltered from the western gales and drift, the beach is reduced to 3 or 4 feet. At the Bill it is only 24 feet above the the present beach. It gradually rises as it trends northward, and is 36 feet above the shore near its north-eastern extremity, and 53 feet at its north-western extremity *. Shells are very numerous at places between Cave Hole and the Sand-holes, but become scarcer on approaching the Bill, and are very rare on the west cliff, where the beach consists of a mass of compact well-rounded shingle, and with little or no sand, whereas on the east side there are also overlying patches, from 1 to 3 feet thick, of shelly sand, full of small shells in a beautiful state of preservation, and in places dug out in small holes. At this part of the beach shells are extremely abundant, especially Litto- rina, Patella, Purpura, Ostrea, and Mytilus, and the original colour of the shells is in many cases in great part preserved. On examining the sand I also found it extremely rich in small species, several of which are new to our raised beaches. The following is the list, for which I am indebted to Mr. Gwyn Jeffreys's obliging assistance : — Bivalves. 16. Littorina litorea, L. 1. Anomia ephippium, Linne. 17. Rissoa parva, Da Costa ; and yar. 2. Ostrea edulis, L. interrupta, Adams. 3. Mytilus edulis, L. 4. Modiola marmorata, Forbes. 18. striata, Ad. 19. subcylindrata, Jeffreys, 5. Cyamium minutum, Fabricius. sp. n. 6. Tellina balthica, L. 20. Skenea planorbis, Fabr. 7. Saxicava rugosa, L., yar. arctica. 21. Purpura la pillus, L. 22. Buccinum undatum, L. Univalves. 23. Nassa incrassata, Milll. 8. Patella vulgata, L. 24. Utriculus truncatulue, Brttguiere. 9. Tectura virginea, Mutter. 10. Trochus helicinus, Fabr. FORAMINIFER. 11. cinerarius, L. Miliola seminulum. 12. umbilicatus, Montagu. 13. Lacuna portiolus, Ticrton. Crustacean. 14. Littorina obtusata, L. Cythere, sp. 15. rudis, Maton. Q. J. G. S. No. 121. d
 * Measured from top of present beach to top of raised beach.