UPPER CHALK. 
83 
from the chalk, but in some instances it is lield 
togetlier by sulphuret of iron, forming a conglo- 
merate of silex and pyrites, of a very singular 
a})pearance. The phenomenon here remarked is 
not, however, confined to this quarry, but may be 
observed in several chalk-pits near Lewes and 
Brighton. 
Sir Henry Englefield was the first who directed 
the attention of geologists to this subject. In a 
paper read before the Linnean Society, he notices 
several beds of shattered flints, which occur in a 
chalk-pit at Carisbrook, in the Isle of Wight ; ami, 
after describing their aj)})earance and situation, 
proceeds to offer some conjectures upon the })ro- 
bable cause of their destruction. This he sup- 
posed might have been occasioned by some sudden 
shock or convulsion, “ which in an instant shivered 
the flints, though their resistance sto])ped the inci- 
pient motion ; for the flints, though crushed, are 
not displaced, which must have been the case, had 
the beds slid sensibly.” * 
Offham pit is nearly two hundred feet high, and 
exhibits a good section of the Sussex chalk. It 
contains the large fibrous bivalve, the fragments of 
which are so frequently met with in every locality; 
teeth and palates of fishes, and numerous zoo- 
phytes. It is the only locality near Lewes in 
which the Marsupifes have been discovered. 
South of this place, in a bank on the road-side, the 
chalk is covered by a bed of ochraceous clay, and, 
where in contact with the latter, the chalk and 
* Linnean Transactions, vol. vi p. lOS- 
G *2 
