434 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 21, 



Series seems to occur right through Kent, at all events through the 

 eastern division. 



6. That the higher and estuarine members (4, 5) of the same 

 series occur only in the western and central parts of the county. 



7. That the pebbles (j3) at the bottom of the Oldhaven Beds (ex- 

 cept at Upnor, where there is a little sand (a) below) are constant, 

 being, however, locally replaced by brown iron-ore in some places 

 near Canterbury. 



8. That in West Kent this series hes irregularly on that below, 

 whilst in the greater part of East Kent the junction of the tivo shows 

 an accidental conformity, although the higher ^xu^ts of the Woolwich 

 Beds are absent. 



9. That it is the lowermost part of each of the three sets of beds 

 which is the most constant, whether from the denudation of the 

 higher parts, or from their more local deposition. 



10. That the true basement-bed of the London Clay is also con- 

 stant, though but poorly represented in East Kent, and that its cha- 

 racter depends on that of the underlying beds : thus, in Berkshire, 

 where the latter consist of clays and sands, it is a loam (mostly with 

 pebbles) ; on the south-east of London, in the neighbourhood of the 

 thick pebble-beds, it is a clayey pebble-bed ; and in East Kent, where 

 the London Clay is underlain by sand, the lowermost foot or so of 

 the former is sandy. 



11. That the higher divisions, the Oldhaven and the Woolwich 

 Series, are transgressive over the Thanet Beds, and occur as outliers 

 on the Chalk at or near its escarpment ; so that what has been 

 thought to show an unconformity between the Chalk and the Ter- 

 tiary system would seem rather to be the result of an uncon- 

 formity in the lower part of the latter. To prove the existence of the 

 first-named unconformity it is needful that the lowest Tertiary bed, 

 the Thanet Series, should be present ; and I think it has been shown 

 that where it is present (in Kent) there is as yet no stratigraphical 

 evidence of unconformity between it and the Chalk : palaeontologi- 

 cally there is a break, and from the examination of a larger tract 

 of country we may perhaps see some signs of the unconformity 

 which that break leads us to expect. 



EXPLANATION OF PLATE XXII. 



{Illustrative of the ^^ Lower London Tertiaries^^ of Kent.) 



The vertical sections in the Plate very likely do not show all the changes in 

 the beds ; but I believe that they show the most important and the best- marked. 

 Full details cannot be given until various Geol. Survey Memoirs are written. 



The small letters and numbers are the same as those of the respective beds in 

 the text. 



No. 1 is made up from the many fine sections in the Canterbury and Reculvers 

 district. 



No. 2 is meant simply to show the local thickening of the pebble-bed (/3) at 

 Shottenden Hill. 



No. 3 is an abstract of a few sections near Sittingbourne, and has been partly 

 drawn with the help of my colleague Mr. Hughes. 



No. 4 is a generalization of the great Upnor sections. 



No. 5 is made from some road-cuttings and pits on the Cobham hills. 



