93 



and festoons of a later date, whose contortions are wholly- 

 unconnected with the changes beneath, and must have been 

 produced by different causes. 



Such a condition of the pebbles is well seen on the 

 actual summit of the chalk crest, 2 miles N.E. of Limpsfield 

 .Church. When the chalk escarpment extended further 

 South, a mile or more, the Darenth stream ran at its foot. 



There can be no doubt that the Darenth extended 

 much further Westward than now, for it is clear as Mr. 

 Topley has remarked,* that there is a distinct relation 

 between the gravels of Limpsfield common and those of 

 the present Darenth valley. The spread of the above 

 mentioned flint pebbles once extended Southward with the 

 chalk, and contributed to form the gravel of Limpsfield, for 

 remains of them in the crushed form, as sand and fine 

 spicules, may be found in parts of the above mentioned 

 gravel, sorted out and slightly waterworn. The main mass 

 of the Limpsfield gravel is much disturbed, and it is im- 

 possible that the pebbles could have reached Limpsfield 

 from the downs in the present state of the escarpment and 

 the contour of the ground. The retreat of the chalk escarp- 

 ment is largely due to surface glaciation, there may be 

 seen an accumulation of coarse surface trail, mingled with 

 shattered blocks of flint crushed out of the chalk, at the 

 sides of the lane leading from the hill above to Titsey. 



At Knock Mill by Kingsdown, is a large mass of 

 tertiary pebbles lying on chalk against Thanet Sand, these 

 have been worked up apparently beneath water. In a section 

 I lately saw, 25 feet deep, there was about midway down a 

 layer of level wash, and signs as if it had all been disturbed 

 by shore ice. Two festooned layers parted by red loamy 

 sand, from 8 to 24 inches deep (land warp), may be 

 distinguished in neighbouring places, the uppermost layer 

 may be traced over the sheet of clay with flints into which 

 it has trailed festoons of pebbles. [PL n-fig. 9.) 



* Weald. 



