SHANKLIN SAND. 
17.5 
served. The mill stands on the ferruginous sand 
with quartzose ironstone ; the argillaceous beds 
constitute the middle j)ortion of the hill: the green 
sand with limestone is seen at the base, forming a 
low escarpment towards the common, which is com- 
posed of weald clay. 
SECTION OK IIENKIELD HILL. 
a. Upper ferruginous beds of the Shaiiklin sand. 
b. Argillaceous or middle division. 
c. Lowermost beds, with arenaceous limestone. 
d. Weald clay. The strata incline to the north. 
In the western part of Sussex, layers of chert or 
hornstone, provin dally termed “ ichinstone,'' pre- 
vail in the sand near Petworth, at Bexley-heath, 
Black-down Hill, &c. The chert above mentioned 
is a variety of hornstone ; it occurs massive, is 
either of a greyish yellow, or greenish colour, has a 
conchoidal fracture, and a glimmering lustre. To 
my excellent friend, John Hawkins, Esq. of Bignor 
Park, I am indebted for the following account of 
its characters and position. 
“ This stone is a compact mass of quartz, but not 
homogeneous, for it contains iron, and perha})s 
some other substance. It occurs in great abund- 
ance in the beds of our building stone, a ragged 
sandstone, which constitutes a chain of hills running 
E. and W. on the north side of the Arun and Bo- 
ther : the strata there have a regular dip to the 
