FROM THE UPPER AND LOWER WHITE CHALK. 17 
NOTE.—CORALS IN FLINTS. 
TuE flints of the Upper Chaik often contain Corals. Usually the destructive silicification has produced 
such loss of structures as to render the specific and often the generic diagnosis impossible. No new species 
have been distinguished in the flints. 
The flint pebbles of the Woolwich series and the basement bed of the London Clay were derived from 
the Upper Chalk principally. In breaking up a series of the pebbles Mr. J. Flower, F.G.S., discovered 
several Corals. A cast of a Trochosmilian (Ccelosmilia, sp. —?) is represented below. 
Cast of a Coral from a pebble. 
Several young simple Corals were noticed by Mr. Flower, but their structures are very badly pre- 
served. 
Section of simple Corals in flint. 
The most interesting fossil of the series is a perforate Coral, with a most delicate lace-like structure of 
its ceenenchyma. Within this Coral is an aporose form, probably a Caryophy/lia. 
Sections of Coral in flint. 
The perforate structure resembles that of the Alveoporz. 
The only example of an aporose Coral which is invariably surrounded by another structure is in Cryptangia, 
a genus whose species are always immersed in Celleporze. It is possible that this Caryophyllia of the 
Chalk was, like Cryptangia parasita, always immersed in a mass of cellular Alveopora. 
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