1865.] FOSTER AND TOPLEY MEDWAT GKAVELS. 449 



Wealdeii pebbles are less numerous here than in the road-cutting 

 to the west. This deposit is certainly an old river-gravel of the Med- 

 way. On the east side of this outlier a different gravel occurs, 

 and is seen along the road going north from Dunks Green. It 

 contains flints and Tertiary pebbles, but no Wealden pehhhs ; at one 

 point a fragment of chalk was found embedded in the gravel ; many 

 of the flints are rather angular and large. 



It must be particularly observed that this deposit, which differs 

 materially in its character from that on the south side of the out- 

 lier, overlooks the transverse valley before mentioned. The stream 

 which comes down this valley from the north traverses only Green- 

 sand and the beds above ; it can therefore only bring down materials 

 contained in those beds. In this small patch of gravel, then, we 

 have abundant evidence, in the absence of Wealden pebbles, in the 

 large size of the flints, and the presence of cIialTc itself, that in 

 former times, when the stream ran at some distance above its pre- 

 sent level, it then, as now, came from the north, bringing down only 

 materials belonging to beds found along its course. We have here 

 preserved the exact junction of the small transverse stream with the 

 main river, which then, as now, brought down debris from the west 

 and south. 



It may be well to notice a similar junction occurring further 

 down the Medway. Between Allington and Aylesford we have, on 

 both sides of the river, evidence of the junction of a stream with the 

 Medway, when both were running 20 or 30 feet above their present 

 level. Just under the railway-bridge, half a mile north-west of 

 Allington Church, 8 feet of gravel is seen in the railway-cutting. 

 The gravel is well stratified, and contains flints and chert with 

 Tertiary and Wealden pebbles, besides numerous rounded fragments 

 of chalk, which have been brought down by the stream which rises 

 at the foot of the chalk hills near Boxley. From this gravel were 

 also obtained fragments of concretionary Wealden ironstone con- 

 taining small Paliidince, also a piece of sheUy ironstone *, with great 

 numbers of Cyclas (or Ci/rena). These specimens, were the Wealden 

 origin of the pebbles disputed, would be sufficient to prove that 

 materials derived from the central districts of the Weald are found 

 in the gravels of the Medway f. 



Similar interstratifications of chalky gravel, with gravel contain- 

 ing Wealden pebbles, are met with along the road just south-east 

 of Cob Tree, near Maidstone. Prof. Morris, in the paper already 

 alluded to J, has noticed the above section, and says that it is re- 

 markable as containing pebbles of chalk, " although it occurs two 

 miles from any chalk in situ." 



Further down the Medway valley we come to an important 

 spread of gravel, which forms a well-marked terrace near Aylesford. 



* A bed of shelly ironstone, not to be distinguished from this, is found ahnost 

 universally at the base of the Wadhurst Clay. Similar beds, perhaps, occur in 

 the Weald Clay. 



t This foct, obvious enough to any one acquainted with the Weald, was first 

 published, we believe, by Mr. Prestwich, Phil. Trans. 1864. p. 267 and Map. 



+ Mag. Nat. Hist. vol. is. (1836) p. 595. 



