TJPPER EOCENE (bARTON AND UPPER BAGSHOT FORMATIONS). 585 



the west, and sink more gradually on the east. In composition they 

 are clay or sandy clay, capped by gravel-deposits, twenty and even 

 thirty feet thick in places, which constantly founder and partially 

 obscure the Eocene beds below. The beds forming this coast-hne 

 beo-in well in the Bracklesham series to the west, and end m the 

 Mfddle Headon, at Paddy's Gap, to the east. The cliifs occupied 

 by the true Barton Series form ruined terraces, and the beds, with 

 few exceptions, can only be seen in situ here and there along the 

 sea-margin. The sea, however, which is rougher than at Bourne- 

 mouth, regularly washes the base of the cliffs in_ the middle of the 

 bay, and exposes an unending succession of fossils. On the other 

 hand, the Hampshire Avon, which for several years swept along the 

 base of Highcliff and threatened to undermine the Castle, has again 

 shifted the direction of its outfall, and left such vast masses and 

 bars of shingle behind, that the sea no longer reaches the cliffs 

 under Highcliff ; and these are consequently assuming an angle of 

 repose, and becoming so overgrown that their stratigraphy, formerly 

 clearly defined, cannot now be made out. This fact helped to decide 

 us to redescribe the Barton Beds without delay. 



The section has been frequently described and measured. There 

 are some slight discrepancies in the thicknesses arrived at, but abso- 

 lute identity cannot be hoped for in dealing with beds whose thick- 

 ness may vary within a few feet. Our measurements were checked 

 on each occasion, the second time by Mr. Geo. Harris, F.G.S. The 

 results are tabulated below, and, for easier comparison, we have 

 taken the maxima and, in some cases, bracketed two or three sub- 

 divisions of other authors together. We have adopted a tripartite 

 system, each division of which is characterized by peculiar fossils 

 and distinct lithological characters. 





4 



•s 

 ^ 



4 

 1 









Becton-Bunny \ Clay, no. 18, Wright 

 Beds J Sand, no. 19, Wright 

 Chamo-hpc\ no '^0 Wriffht 



25 

 20 

 15 

 50 



80 



30 



30 



20 



150^ 



70 



15 



23 

 19 

 15 

 50 



50 



14 



26 

 26 

 18 

 53 



49 



10 



Upper Barton, b of 

 Prestwich. 



Middle Barton, part a 



of Prestwich. 

 Lower Barton, part a 



of Prestwich. 



Barton Olav no 21 Wrifflit 



Highdiff Beds, nos. 22, 23, 24, base 



Green sandy clay and pebble-bed ... 

 Total 



190 



315^ 



171 



182 



Bracklesham 



... 





... 



45 





The Bracldesham Beds at Highcliff form a vertical escarpment 

 45 feet high, of compact white sand, with an admixture of carbo- 



* This measurement appears due to a lajpsus calami. 



