540 
THE CRETACEOUS ROCKS OF BRITAIN. 
material when dried is said to form a “ hard, light-coloured cal¬ 
careous mass," it appears to be a kind of calcareous ooze. A sample 
from which most of the fine impalpable ooze had been removed 
was examined by Dr. Brady, who found the components to be as 
follow, stated in proportion by weight : — 
per cent. 
Bilocublina ringens (one-half being entire shells) - - - 50 
Haplophraginium latidorsatum ------ 20 
Globigerina borealis .- - - 4 
Sand with a few other Foraminifera ----- 20 
Impalpable debris - - - - - - - - 6 
It is distinctly stated that the mass of this material consists of finely 
divided matter, and that the Biloculinm do not amount to more 
than 2 per cubic centimetre. 
To sum up, therefore, we believe that the white chalk of 
England and France is a deep-sea foraminiferal deposit comparable 
with Biloculina ooze and with the lower layers of Globigerina ooze, 
but not identical with either. We believe that the disintegration 
of the organisms which have furnished the material of the cal¬ 
careous matrix was accomplished beneath the floor of the Cretaceous 
sea, and that several kinds of organisms have contributed to its 
formation, one predominating at one time and one at another. 
Among these, Spheres and shell-fragments are frequently as 
numerous as the tests of Foraminifera. 
