THE OCEAN OF THE CHALK. 
343 
remains which they enclose, prove that the chalk 
was deposited in the tranquil depths of a profound 
ocean ; the abundance of AmmoniteH^ Nautili, and 
other multilocular shells that inhabit the bottom of 
the deep * ; the almost entire absence of pebbles and 
gravel t ; the perfect state in which the fishes and 
other perishable organic bodies occur — not as in the 
We^ilden, crushed, and disjointed, but as perfect 
as if they had been enveloped by a soft piste when 
living, or even while in a state of progression — all 
bear evidence in favour of such a conclusion.! 
There are but few, if any remains of terrestrial 
animals and plants, to throw liglit on tlie nature of 
the climate during the cretaceous epoch : we may, 
however, infer from the nautili and other tropical 
shells, as well as from the presence of the stony 
polipidoms, or corals, tliat the temperature was not 
muchinferior to thatof the Iguanodon period, for this 
* “ The recent Xautilus pompUius is a ground-dwelling animal, and 
its principal sphere of action is at the bottom of the sea, as is proved 
by the nature of its food. The peculiar structure of its shell enables 
it to rise to the surface ; but to float there at ease, an additional volume 
of air is probably taken into the dwelling chamber; in which case the 
act of sinking would be accomplished by simply reversing the shell.” 
In several ammonites and nautili from the Sussex chalk, the siphun- 
culus, or air-tube, which communicates with the concealed chambers 
of the shell, is beautifully preserved. — Consult the highly interesting 
and scientific Memoir on the Pearly Nautihis, by Richard Owen, Esq., 
of the Royal College of Surgeons of London. 4to. 1832. 
Small quartz pebbles occur in the chalk of Kent ; and, very rarely, 
in that of Sussex. I have a flat pebble from Steyning, 3 inches in 
diameter, to which are attached a small caryophillia, and several minute 
parasitical shells. 
:}; These remarks, of course, refer to the chalk of this part of Eng- 
land only ; the chalk ocean, like other seas, must have had its shallows, 
and its limits ; and, probably, sooner or later, traces of its shores, and 
beds of shingle, and sand, with littoral shells, will be discovered. 
z 4 
