Ch. XXI.] CHALK ESCARPMENTS ONCE SEA-CLIFFS. 
291 
valley excavated chiefly out of the argillaceous or marly bed, 
termed Gault (No. 2). The escarpment is continuous along the 
southern termination of the North Downs, and the reader may 
trace it from the sea at Folkstone, westward to Guildford and 
the neighbourhood of Petersfield, and from thence to the ter- 
mination of the South Downs at Beachy Head. In this preci- 
pice or steep slope the strata are cut off abruptly, and it is 
evident that they must originally have extended farther. In 
the accompanying wood-cut (No. 65), part of the escarpment 
of the South Downs is faithfully represented, where the denu- 
dation at the base of the declivity has been somewhat more 
extensive than usual, in consequence of the upper and lower 
green-sand being formed of very incoherent materials, the 
former, indeed, being extremely thin and almost wanting. 
The geologist cannot fail to recognize in this view the exact 
likeness of a sea-cliff, and if he turns and looks in an opposite 
direction, or eastward, towards Beachy Head, he will see the 
same line of height prolonged. Even those who are not 
accustomed to speculate on the former changes which the sur- 
face has undergone, may fancy the broad and level plain to 
resemble the flat sands which were laid dry by the receding 
tide, and the different projecting masses of chalk to be the 
headlands of a coast which separated the different bays from 
each other. 
No. 66. 
Chalk escarpment as seen from the hill above Steyning, Sussex. The castle and village of 
Bramber in the fore- ground. 
Lower terrace of firestone.-~-We have said that the upper 
U2 
