Geological Society. 103 



nidse, and this again overlies a sandstone abounding with silicified 

 bones of gigantic sharks mingled with extinct species of oysters and 

 Pernse of a great size. The intermediate bed contains some shells in 

 common with the upper, in which all are recent, and with the lowest, 

 in which the greater number are extinct. The phenomena of the 

 parallel terraces and the elevated shells occur in a strongly marked 

 manner in the villages of Guasco and Copiapo, the latter being 350 

 miles to the north of Valparaiso: recent shells also occur at different 

 elevations at an equal distance to the south of it at Concepcion and 

 Imperial. Mr. Darwin believes that the land on the coast of Chili has 

 risen, though insensibly, since 1822. In the island of Chiloe he is fully 

 convinced, from oral testimony and the state of the coast, that a change 

 effected imperceptibly is now in progress. In support of this gradual 

 rise, independent of earthquakes, he states, that the eastern coast of 

 South America, bordering the Atlantic from the Rio Plata to the Strait 

 of Magellan, presents terraces containing recent shells ; yet in the pro- 

 vincesnearthe mouth of the Plata, earthquakes are never experienced j 

 anditisimpossibleto suppose that themost violentofthe Chilian earth- 

 quakes could produce these effects, as the shocks are scarcely trans- 

 mitted to the plains at the western foot of the Cordilleras. Hence, he 

 concludes that the earthquakes, volcanic eruptions, and sudden ele- 

 vations on the coast line of the Pacific, ought to be considered as ir- 

 regularities of action in some more widely extended phenomenon. 



January 18.— A paper entitled, "An Account of a deposit con- 

 taining land shells at Gore Cliff, Isle of Wight," by J. S. Bowerbank, 

 Esq., F.G.S., was first read. 



During a recent examination of the greersand of Gore Cliff, Mr. 

 Bowerbank discovered on the top of the cliffand overlying the chalk 

 marlbywhichitis capped, abedconsistingof detritus of chalk andchalk 

 marl, and inclosing, in every part examined by him, numerous spe- 

 cimens of existing species of land shells. The deposit extends from 

 nearlytheedgeoftheclifftothefootof St.Catherine'sDown, a distance 

 of about 660 yards. The range of the deposit he could not ascertain, 

 as at a short distance from the spot examined the cliff assumed 

 its usual perpendicular form ; but he is of opinion that it is consider- 

 able, or else that there are many such deposits, as he found fallen 

 masses of a similar bed near St. Lawrence and between Ventnor 

 and Bonchurch. 



A letter addressed to Dr. Buckland by J. Wyatt, Esq., respecting 

 a trap dyke in the Penrhyn Slate Quarries near Bangor, Carmarthen- 

 shire, was then read. 



These quarries were opened fifty years since, and the excavation is 

 now about 700 yards in length, 300 in breadth, and 90 below the 

 natural surface. In carrying on the highest opening of the quarry, 

 the men, a few months since, came suddenly in contact with a trap 

 dyke, which has since been cut through and proved to be 11 feet in 

 width. Its direction appears to be between W.N.W. and N.W., and 

 it intersects the bedding of the slate nearly at right angles. The dip 

 at present is almost 90°, the slight inclination being to the N.E. The 

 i( cheeks " of the dyke on the N.W. side, are broken conformably with 



