308 Royal Institution. 



the British Association at Southampton, expressed his belief that 

 Hempstead Hill, near Yarmouth, would prove to be composed of 

 strata higher than those of Headon ; and the Marchioness of Hastings, 

 who, having; given much time to the search for the remains of fossil 

 vertebrata in the tertiaries of the Isle of Wight and Hordwell, 

 declared her conviction that these remains belonged to distinct 

 species, according as they were collected at Hordwell, Hempstead, 

 and Ryde, and that these three localities could not, as was usually 

 understood, belong to the same set of strata. The recently pub- 

 lished monograph of the pulmoniferous mollusks of the English 

 Eocene Tertiaries, by Mr. Frederic Edwards, afforded also indications 

 of the shells therein so well described and figured having been col- 

 lected in strata of more than one age. 



A few days' labour at the west end of the island convinced Pro- 

 fessor Forbes that the surmises alluded to were likely to prove true, 

 and that the structure of the north end of the island had been in the 

 main misunderstood. After four months' constant work at both 

 extremities and along the intermediate country, he succeeded in 

 making out the true succession of beds, with most novel and gratifying 

 results. During this work he was greatly aided by his colleague, Mr. 

 Bristow, and by Mr. Gibbs, an indefatigable and able collector 

 attached to the Geological Survey. 



The freshwater strata of Whitecliff Bay proved to be wholly mis- 

 interpreted. Instead of their being constituted out of the Headon 

 Hill strata only, more than a hundred feet thickness of them are 

 additional beds characterized by peculiar fossils, and resting upon a 

 marine stratum that overlies the Bembridge limestone, the equiva- 

 lent of which at Headon is a soft concretionary calcareous marl, 

 scarcely visible except in holes among the grass immediately under 

 the gravel on the summit of the hill. 



The beds of the true Headon series, in fact, are all included in the 

 subvertical portion of the Whitecliff sections and are there present 

 in their full thickness. They are succeeded by peculiar strata of 

 intermediate character, for which the name of St. Helen's beds is 

 proposed, and which become so important near Ryde that they con- 

 stitute a valuable building stone. The Bembridge limestone that 

 lies above is the same with the Binstead limestone near Ryde, out 

 of which were procured the remains of quadrupeds of the genera 

 Anoplotherium, Palaotherium, &c, identical with those found in the 

 gypsiferous beds of Montmartre. The Sconce limestone near Yar- 

 mouth is also the same, and none of these limestones are identical with 

 any of those conspicuous among the fluvio-marine strata at Headon 

 Hill, and with which they have hitherto been confounded. They are 

 far above them, and are distinguished by distinct and peculiar fossils. 

 Almost all the country north of the chalk ridge, exclusive of the 

 small strip occupied by the marine Eocenes, is composed of marls 

 higher in the series than any of the Headon Hill beds, and hitherto 

 wholly undistinguished, except in the Whitecliff section, where the 

 age and relative position had been entirely mistaken. These are the 

 Bembridge marls of Professor Forbes. Above them are still higher 

 beds preserved only in two localities, viz. at Hempstead Hill, to the 

 west of Yarmouth, and in the high ground at Parkhurst. For these 



