By A. J. Jukes-Browne, B.A., F.G.S. 237 
separated by layers of hard green-coated nodules, and no one who 
has once seen it would mistake it for any other bed in the Chalk. 
So also, when a thin slice is viewed under the microscope, it is seen 
to have a structure which is different from any other bed, and Mr. 
W. Hill, F.G.8., writes that ‘“ no one who has seen a slide prepared 
from this rock will mistake it for Chalk from any other horizon.” 
It is simply crowded with Foraminifera and with broken fragments 
of shell and other organic remains; sponge spicules are common, 
and there are large grains of Glauconite like those which occur in 
the Greensand far below. 
Figs. 5 and 7 illustrate this structure: Fig. 5 is the reproduction 
Fig. 6.—Structure of Middle Chalk, engraved from a drawing by 
F. Rutley, Esq., F.G.S. 
of a beautiful photograph by Mr. Freshwater, and shows very well 
the number and variety of Foraminifera which sometimes appear in 
a single slice. Fig. 7 is a woodcut by Mr. Cooper, from a drawing 
made by Mr. F. Rutley, F.G.S., and exhibits still better the different 
kinds of organisms which are often crowded into a small area of 
Chalk rock. A sponge spicule cut transversely is seen at 3, a 
grain of glauconite at j, and a fragment of Echinoderm shell at g, 
while the large object above this is a Foraminifer (Vernewillina). 
