DRIFT-STAG i:S OF Tlli: DAKENT VALLEY. 



151 



of about a ton in weight of a sandstone-and-flint-breccia (Lower 

 Tertiary) may be seen on the side of the road north of the Kennels 

 at Otford. It is probable that there were others which have been 

 broken up. 



Some of the angular Lower-Greensand drift below Seal Chart 

 and at Seal, and the angular flint-debris north of Child's Bridge, 

 may possibly be of this date. 



i should here observe that there is not infrequently, in this as 

 in other districts, an apparent passage between one level of gravel 

 and another, caused by a trail ])assing from the higher to the lower 

 level, and so covering the slopes which separate the two drifts 

 that they appear to form a continuous bed. This might easily lead 

 to mistakes. 



[Since writing the above, a cognate enquiry in which I have been 

 engaged has led me to suspect another agency to which the angular 

 patches of drift may be due. This has resulted in a drift which 

 assumes so many phases that a revision of some portion of the lower 

 drift-beds of this district may prove necessary, but it does not inter- 

 fere with the delinition of the higher-level valley and plateau drifts.] 



§ 8. The Low-Level Valley- Gravels. 



There are other drift-gravels in this valley, but they are more 

 isolated and their correlation more uncertain. The most con- 

 spicuous outlier is the one between Otford and the " Bat and Ball " 

 Station at Sevenoaks. It is one mile east of Broughton Hill, and 

 on the opposite side of the Darent. The annexed section gives its 

 position in relation to the several gravel-beds before described. 



Fig. 10. — Section from Diinton Green to tlie Otford and 

 Sevenoaks Bead. 



w. 



Broughton 

 Hill. 

 357. 



Rye 

 House. 



2134. 



Darent 



Otford 



R. 



Brick-pit 



200. 

 1 



234. 

 1 



1 



E. 



b. Gravel of the LimpsOeld level. 



(L Gravel of the Chevcning level. 



(/. Low-level river-gravel. 



2. Lower Chalk. 3. Gault. 



Although so near, this gravel is very distinct from that on 

 Broughton Hill or at Dunton Green. It is irregularly bedded, with 

 veins of grey sandy clay, and consists in larger part (60 per cent.) 

 of subangular fragments of Chert, Ragstone, and Ironstone from 

 the Lower Grccnsand, with a lesser proportion of subangular 



