FIRESTONE OF SOUTHBOURN. 
lOl 
places, in the state of sand ; in others, forming a 
stone sufficiently hard for building. The transition 
from the marl to the firestone is in many local- 
ities so gradual, and the sandy particles are so 
sparingly distributed, that the chalk marl may be 
said to repose immediately on the gait ; in others, 
however, the characters of the firestone are very 
})eculiar, and some geologists have deemed them 
sufficiently important to rank tliis dejiosit as an 
independent formation. 
d'he low cliffs, near Southbourn, expose a sec- 
tion of the arenaceous variety of tlie firestone. 
East^^^ard of Beachy Head, and to the west of 
Holywell quarries, the chalk marl is seen under 
the chalk without flints, dipping about 5 ° to the 
; proceeding along the beach, a bed of 
greyish sand emerges from beneath the marl, to 
the east of the first martello tower ; this quickly 
rises, till it constitutes one half of the cliff, and 
beneath it is seen a stratum of friable sandstone of 
a deep green colour ; at the distance of about 
forty or fifty yards, the clifi‘, which is twenty feet 
high, is entirely composed of these strata, with the 
exception of a covering of alluvial loam on the 
summit. The alluvial tract called “ the wish” 
obscures the beds near this spot, but they re-appear 
at about a hundred yards to the eastward, where 
the firestone forms the base of the cliff, and is 
* Tlie lowermost bed of nuirl, and which is in contact with the fire- 
stone, is almost wliolly composed of the remains of ramose milleporites, 
madreporites, &c., so as to form a ridge or reef of corals : in this bed 
we found a long cylindrical zoophyte of the same kind as those which 
occur in the vale of Pewsey, in Wiltshire; it is partly composed of 
chert. 
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