FITTON ON THE ATHERFIELD AND HYTHE SECTIONS. 179 



There is only a fragment of this Ammonite in the collection. It pre- 

 sents, however, excellent distinctive characters in the outer whorl, which 

 is compressed, and so large as apparently to have enveloped, or nearly enve- 

 loped, the others. It is marked with radiating strias or rather furrows, 

 which are unequal and slightly undulated. These are separated into 

 groups by wider, distant, shallow sulcations. The back is flattened, slightly 

 excavated, and bounded by an obsolete keel or angle at each side, over which 

 the lateral stria? turn obliquely, but become obsolete before they reach the 

 hollow of the centre, which appears to have been smooth. The aperture 

 was probably ovato-lunate in form. Belongs to section Dentati, and is 

 nearly allied to several gault species. 



14. Rostellaria angulosa D'Orbigny, 1. c. pi. xviii. f. 4. 



15. Lucina plicaio-costata D'Orbigny, 1. c. p. 83. pi. xviii. f. b. 4. 



16. Venus chia D'Orbigny, 1. c. p. 82. pi. xviii. £ 9, 10. 



17. Inoceramus lunatus. Nov. sp. 



/. testa suborbiculari, obliqud, plana, sulcis concentricis regularibus latis, in- 

 terstertiis angustis elevatis acutiusculis. 



The only specimen of this well-marked Inoceramus is imperfect. The 

 characters of the surface are, however, well displayed, and a portion of the 

 hinge is shown. The sulcations of the surface are lunate, broad in the cen- 

 tre, narrow at the sides, and very regularly formed. The intermediate ribs 

 are narrow, and slightly or obsoletely ridged ; they slope away into the fur- 

 rows more suddenly anteriorly than posteriorly. The fragment measures 1 \ 

 inch in length, by 1^ in breadth. 



2. Comparative Remarks on the Sections beloio the Chalk on the 

 Coast near Hythe, in Kent, and Atherfield, in the Isle of 

 Wight. By W. H. Fitton, M.D., F.R.S. 



My objects in this paper are to illustrate, 1st, two sectional 

 elevations, showing the proportional thickness of the principal 

 divisions of the strata at Hythe and Atherfield ; 2dly, an approx- 

 imate sketch of the cliffs from Atherfield to the East of Black - 

 gang-Chine ; and 3dly, a corresponding sketch of the section from 

 the chalk hills above Folkstone, to the level of the sea at Hythe. 

 §. The Atherfield Section is a copy of a drawing made by Sir John 

 Herschel, referred to in the fourth volume of the Geological Trans- 

 actions * : I have engrafted upon it such farther information as has 



* Second Series, vol. iv. p. 186. 

 n 2 



