264 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 4, 



Vienna and Mayence basins, and others in Portugal, Spain, Malta, 

 Corsica, Greece, &c. Of these many have been hitherto always 

 described as Miocene. 



In the Isle of Wight, the series of beds, from the uppermost of 

 the Hempstead series to the Barton clays (not to speak of the re- 

 mainder of the Eocene series), is in perfect conformity throughout, 

 and, whilst the distinctive palseontological features of the several sec- 

 tions are unmistakeably defined, each group is linked with its neigh- 

 bours by fossils common to it and them, in a manner clearly indica- 

 tive of perfect geological sequence. The line drawn by foreign geo- 

 logists between Miocene and Eocene is, if I am right in my compa- 

 risons, that which I have dra\Mi between the Hempstead and Bem- 

 bridge groups. But in the Isle of Wight this line is more conve- 

 nient on accouut of mineral and topographical features, than because 

 it marks any interruption of continuity. In truth these two groups 

 pass into each other. Bearing in mind, then, the discordance between 

 the Touraine Faluns (the typical Miocene of Sir Charles Lyell) and 

 the so-called "Lower Miocene" in France, as well as the great 

 distinctness of their fauna, I think the facts which I am bringing 

 forward in this notice should go far towards the assignment of the 

 Gres de Fontainebleau and its equivalents to the Eocene or Older 

 Tertiary epoch. 



Although, in a full memoir upon this subject, which will appear 

 hereafter in the " Records of the Geological Survey," I shall describe 

 in minute detail the phsenomena of the Headon beds and underlying 

 sands exhibited at Headon and in Colwell and Whitecliff bays, it is 

 scarcely necessary to do so at present, since so many and able accounts 

 of them have appeared from time to time, and several have been 

 published by the Society. The sections of the fluvio-marine beds 

 of Headon Hill by Mr. Prestwich, that of Colwell Bay by Dr. Wright, 

 and those of Whitecliff Bay by Mr. Prestwich, Capt. Ibbetson, and 

 myself, all enumerate the succession of beds in detail. After the pub- 

 lication of the two first-mentioned, it seems difficult to understand 

 how M. He'bert has come to the conclusion that the Colwell beds are 

 distinct from and higher than the strata in Headon Hill. In con- 

 junction with Mr. Bristow I have carefully and minutely made fresh 

 separate sections of each of those localities as they appeared last year, 

 with notes of the fossils of every bed, carefully examined on the spot. 

 The apparent differences depend upon the more marine character 

 of the " Upper Marine " or Middle Headons at Colwell, than at 

 Headon, a difference similarly marked at Hordwell, and still more at 

 Whitecliff. 



The freshwater limestones, which constitute so conspicuous and 

 important a part of the section at Headon Hill, pass into soft beds 

 northwards, and very soon appear to have entirely vanished, or 

 rather to have been represented by clays and marls westward, so 

 that in the sections at Whitecliff Bay they are no longer recognizable. 

 Influenced by their dominant character at Headon, however, all geo- 

 logists who have described the Whitecliff section, or any other tertiary 

 portions of the Isle of Wight, have identified with them, or rather 



