520 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [JuilO 17, 



to the intermediate beds, which may be found, even when hidden by- 

 sand, by measuring from the stone bands. 



The Brachlesham beds are well exhibited on the shore. The bed 

 of lignite, 6 feet thick, in Mr. Fisher's division Y, is continuous for 

 at least 200 feet. The clay below is penetrated by veins of the 

 lignite, at first sight resembling the roots entering the underclay of 

 a coal-seam, but on examination proving to be veins. 



The London Clay is visible on the shore throughout its thick- 

 ness of 299 feet. 



The Plastic Clay was seen on the shore at intervals. Its thick- 

 ness is about 200 feet, as measured on the 2-5VD" scale Ordnance Map. 



Comparing the section at Whitecliff Bay with the section measured 

 at Alum Bay by Mr. Bristow of the Geological Survey, it appears 

 that the total thickness, from the Chalk to the base of the Fluvio- 

 marine series, is the same at both points, although the thicknesses 

 of the component formations differ considerably. 



Plastic Clay 



London Clay 



Lower Bagshot 



Bracklesliam and Barton 

 Upper Bagshot 



Thickness at 

 Whitecliff Bay. 

 feet. 

 200 

 299 

 142 

 710 

 158 



Headon. 



1509 

 168 



Thickness at 

 Alum Bay. 



feet. 

 84 



219 



660 



411 



122 



1496 

 181 



1677 

 Fossils from the Headon Series. 



1677 



Bed L. 



Avicula, 



Ostrea prona ( S. V. Wood). 



Ostrea. 



Cardium Laytoni ? 



Cardita deltoidea. 



Corbula cuspidata. 



Ostrea prona {S. V. Wood). 

 Cardium porulosum. 



semigranulatum. 



Cardita deltoidea. 



Corbula cuspidata. 



Nucula. 



Psammobia compressa. 



Sanguinolaria. 



Tellina. 



Cytherea incrassata. 



suberycinoides. 



Cytherea. 



Buccinum labiatum. 

 Bulla elliptica ? 

 Bulla. 



Bed M. 



Cytherea incrassata. 



Cytherea. 



Calyptrsea trochiformis. 



Fusus. 



Voluta sukiralis ? 



Lamna. 



Calyptrasa trochiformis, 



Cancellaria evulsa ? 



Conus dormitor (seminudus). 



Pleurotoma plebeia. 



Ditrupa. 



Melania, 



Fusus. 



Natica labellata. 



Natica. 



Eostellaria rimosa. 



Tornatella. 



Lamna. 



G-raphiolaria Wetherelli. 



Retepora. 



