PRESTWICH BRITISH AND FOREIGN TERTIARIES. 109 



2. Section of the cliff' at Alum Bay, Isle of Wiyht. 



Feet. 



b. Pure white siliceous sands, with yellow clay at base 100? 



r Dark-grey clay, with septaria and few shells 95 



Bark clayey green-sand, with few fossils 65 



J Brown and grey clay with Nummulites, passing into clay 

 ' "S mixed with green-sand ; layers of septaria ; — shells nu- 



I merous 119 



I, Basement-bed of flint-pebbles, very large 1 



;iso 



Orof— 



Siliceous sands 100 feet. 



Clays 280 „ 



3. Section of the cliff at White Cliff Bay, Isle of Wight*. 



Feet. 

 b. Yellow siliceous sands : casts of marine shells in some 



of the beds about 202 



Laminated brown clay and greenish sand 



Yellow siliceous sand 



Brown and grey clay, witl i fossils 



a. •{ Band of grey siliceous sandstone 



Light-grey and brown clay — Corbula, Nummulites. 



Striped ochraceous and white sands 



- Largish flint-pebbles and ironsand (basement-bed) 



490 

 Orof— 



Siliceous sands 263 feet. 



Clays 227 „ 



The above particulars do not give the full details of all the beds, 

 but they give the general and prominent mineral masses. In the 

 Barton section the top sands vary in thickness from 10 to 15 feet ; 

 at Beacon-Bunny the underlying clay measures about 20 feet tj and 

 thickens westward to about 40 feet, including the subordinate bed of 

 siliceous sand. Occasional seams of flint-pebbles occur through the 

 lower beds " « " in all three places, but they are always small and 

 unimportant, and mark no line of break as the larger layer of pebbles 

 at the base of the series does. Green sand, in small quantities, is 

 mixed with almost all the clays ; and all the parts of " a " may be 

 considered as parts of one mass. These beds immediately overlie 

 the sands of the Bracklesham series. The sands " b"" are in each 

 case overlied by the green freshwater clays ; but at the Barton sec- 

 tion a thin bed of sand, full of sestuarine shells, is interposed between 

 the Barton sands and the freshwater clays. 



* See my paper in Journ. Geol. Soc. vol. ii. pp. 253-257. These sections diflFer 

 from my former ones by some additional details which I have since been able 

 to observe. No. 2 section corresponds with strata Nos. 29 and 30 ; and No. 3 

 section with strata No. 14 (part of) to 20 of that paper. 



t These are known as the Beacon-Bunny beds, and contain a peculiar group of 

 brackish-water shells. 





37 





44 





157 





5 





32 





12 





1 



