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C. PARKINSON ON THE ISLE-OF- WIGHT 



27. Uppee Greensand and Chloritic Marl, Isle of "Wight. 

 By C. Parkinson, Esq., E.G.S. (Read March 23, 1881.) 



Although the Isle-of- Wight Greensands have been well explored by 

 eminent geologists, such as Eitton, Mantell, Ibbetson, and Saxby, 

 there yet remains ample work for palaeontologists in the classifica- 

 tion of the fauna characteristic of each horizon. Hitherto the 

 fossils from different zones have not been clearly separated, the 

 collections from the Malm rock being mixed with those of the 

 upper cherts and rags, and the Chloritic Marl with both. In form- 

 ing a collection illustrative of the above series, it has been the writer's 

 aim to divide every zone and to define the extent of each. 



At the base of the section a band of chert nodules is indicated, 

 measuring 2 feet, which is possibly the true junction of Gault and 

 Greensand, although in the Memoir on the Geological Survey of the 

 Isle of Wight 50 feet of micaceous sands below this point have been 

 included in the Greensand ; this has also been done more recently 

 by Dr. C. Barrois, of Lille. It was from this section, exposed on 

 the St. -Lawrence beach, that Captain Saxby procured a species of 

 Crayfish ; and a second specimen has been found within the last 

 eighteen months in the same locality. The importance of this 

 horizon has apparently been overlooked ; for quite recently a further 

 valuable addition has been made to the fauna by the discovery of a 

 Chelonian previously unknown to palaeontologists. Prom Captain 

 Saxby's day to the present time the locality has been neglected. 

 About a year ago Mr. Mark Norman, a well-known local geologist, 

 noticed a huge boulder of this blue chert lying exposed to the wash 

 of the tide ; it had certain indications on the exterior which led 

 him to examine the whole surface with care ; there were, in fact, 

 the perforations of bone clearly shown. With great care the 

 hard matrix was chiselled out, revealing portions of the carapace 

 and rib-bones of a Turtle of the family Paludinosa. The specimen 

 is now in the Natural-History Museum, South Kensington ; and 

 through the courtesy of Prof. Owen I am enabled to give the 

 following notes, abridged from a description kindly made by him. 

 It is referred to the 



Order CHELOMA. 

 Earn. Paludinosa. 

 Genus Plastremys, Owen. 

 Plastremys lata, Owen. 



A new genus and species of freshwater Tortoise from the Isle- 

 of- Wight Greensand, remarkable for its breadth in proportion to 

 length. In this character it approaches nearest to the Tertiary 

 Emys Icevis ; but the transverse dimension is not eked out, as in that 

 species, by the accessory plastral plates, and the plastral portions of 

 the marginal plates are respectively less broad in Plastremys, and 



