282 



THE GEOLOGIST. 



witli or merges into great drifts of angular flint-gravel, bnt in the area 

 we are traversing the brick- earth is very pure and free from any con- 

 siderable quantity of fragmentary flints. 



It must be borne in mind that the plain over which we have been 

 walking, although at the foot of the lofty chalk dov/ns, is still at a 



Lign. 21. — Chalk Downs, near Folkestone. 



high level above the sea, and forms the continuation of that high 

 ground of the Gault and Lower Greensand at Folkestone, which con- 

 stitutes the West Cliff, and is cut off from the East Cliff or Copt Point 

 by a valley from eighty to ninety feet deep, in which a considerable part 

 of the old town is built. In this valley several springs of beautifully 

 clear water break out, the most noticeable being that at the " Bull- 

 dog steps," which even in the driest and hottest seasons pours forth 

 in undiminished flow. 



At the south-eastern corner of the West Cliff, under the Battery, 

 lying immediately on the upper beds of the Lower Greensand, which 

 are of loose disintegrated sand, is the Pleistocene ossiferous deposit, 

 from one to nine feet thick, to which we alluded at page 125. It con- 

 sists of flint- pebbles, boulders, and fragments of ferruginous sand- 

 stone, intermixed wiih loamy sand and surmounted by calcareous 

 marl. This bed extends along the fjice of the cliff for a distance of 

 three hundred and twenty feet, following the iiTCgularities of the 



