PRESTWICH WOOLWICH AND READING SERIES. 107 



Fig. 11. — Lane in Abbey Wood. 



_^^,...-'-r: Feet. 

 I. Basement-bed of London 

 I- day* (flint shingle- 

 beds) + 10 



II. Light green sand with 



-"^ II. seams of pebbles; 



=--=::=gvvr7eS traces of laminated 



— ^^^ clays occur at b 14 



1 iir. III. Thanet Sands +20 



Numerous small sections of the fossiliferous clays and associated 

 beds may be seen on the higher hills between the valleys of the Cray 

 and the Darent, as at St. Paul's Cray Hill, Well Hill, Croking Hill, 

 Joyden Wood's Hill, and elsewhere ; and again, east of the Darent, 

 on the Swanscombe Hills near Greenhithe, on Windmill Hill, Graves- 

 end, and on the Shorne and Cobham Hills near Strood. The section 

 east of Bexley on the hill leading to Dartford Heath, the one between 

 Green Street Green and Betsham, and that traceable on the path and 

 road-sides in descending from the summit to the south side of Wind- 

 mill Hill, Gravesend, are represented under the Loc. sect. 29, 30, 31, 

 and 32, Diag. A, PL I. The section at Shorne, Loc. sect. 33, is taken 

 in the lane leading from the high-road near Gad's Hill to Shorne 

 Ridge way. 



At Upnor near Rochester the section, which is unusally clear and 

 distinct, shows the London clay with its Basement-bed reposing upon 

 the fluviatile sands and clays, which in their turn overlie the Thanet 

 Sands. These latter, however, do not appear in the larger pit where 

 there is the capping of London clay, but in the sand-pit by the brick- 

 field to theS.W. of it. (See Journ. Geol. Soc. vol. viii. pi. 15.) 



The general view of the pits is as follows : — 



(PI. L Diag. A, Loc. sect. 34.) Feet. 



London clay +25 



I. Basement-bed of the London clay 4^ 



fc. Light yellow and whitish sands, containing irregular 

 patches of shells, chiefly Ostrea and Cijrena; occa- 

 sionally the shells form a layer 1 ft. thick at the base 

 of this bed. Upper surface worn and eroded by " i." 15 

 Dark grey clay full of shells, both perfect and com- 

 minuted, and with a subordinate thin seam of sand, 

 3 2" feet. Dark clay passing down into a brown sandy 

 clay — a few casts of shells — selenite plentiful, 2 ft. 

 Tough yellow clay, sand and ochre, and lignite, ^ ft. 6 

 Fine white sand 2 ^ feet. Sand, grey and brownish- 

 red at top, passing down into light yellow, 20 ft. 

 Light ochreous sand, 3 feet. Small flint-pebbles in 

 greenish sand, 2-| ft 28 



III. Thanet Sands +20 



* In a cutting on the side of the new road just made a short distance east of 

 this section, the " Basement-bed " reposes upon the pebbly sands of the Wool- 

 wich and Reading series. The division of these two groups is here perfectly 

 well shown, the line of separatiou being distinct and irregular, and the peblily 

 sands, which are far more pebbly than at Woolwich, and contain numerous very 

 friable and badly preserved shells, chiefly Cyrena, being in clear contrast with the 

 overlying mass of non-fossiliferous and larger shingle. 



Woolwich 



and 

 Reading 

 Series. 



