516 
THE CRETACEOUS ROCKS OF BRITAIN 
large and coarse, many showing the perforated structure 
of those seen in the Beer Stone. Inoceramus prisms 
are rare; there are also other particles, evidently of shell, aud 
two or three small Echinoderm spines. No sponge-spicules are 
present. Glauconite in small green grains is rare. 
From the Middle of the zone, Beer Harbour. — Chiefly amorphous 
material; many Spheres and foraminiferal cells occur, though 
they are not so abundant as in the specimens from lower in the 
zone; larger forms of Glohigerina and Textularia are rare; all 
have their cell walls weakly outlined. There are many small 
shell-fragments. 
The amount of recognisable organic particles may he estimated 
at about 35-40 per cent. 
Results of the Examination of Washings. 
Specimens both of the higher and lower part of this zone from 
Dover and from Hitchin were washed with water, and an 
attempt was also made to wash others from Mupe Bay (Dorset), 
Louth (Lincolnshire) and Hessle (Yorkshire), but the chalk from 
these localities was too hard to yield satisfactory results. 
Shell Fragments . — Inoceramus-prisms were common in all 
specimens, but that from the higher part of the zone at Dover 
contained many fragments easily recognisable as those of Tere- 
bratulina; none were observed in the Hitchin sample. A few 
plates and pieces of rather large spines of Echinoderms occurred 
at both places. 
A feature of the washings was the abundance of minute cal¬ 
careous plates or ossicles. They w r ere not like the smooth marginal 
ossicles of Groniaster (which also occur commonly), but have a 
complicated form rather difficult to describe, scarcely any two being 
exactly alike. Dr. Gregory, who kindly examined some of these 
ossicles at our request, says “ they are the ambulacral ossicles of an 
Ophiurid, but to determine the genus is difficult.” These peculiar 
plates or ossicles first appear in the top of the Lower Chalk, are 
fairly abundant in the Belemnite marls at Dover, but seem to be 
most numerous in the zones of the Middle Chalk. 
Sponge-spicules are of rare occurrence, and have only been noted 
in the thin section of hard beds near the top of the zone. 
Forammifera. — The list of Foraminifera isolated from washings 
and residues is not large. Judging from the amount of material 
from Hitchin and Dover which was washed, these forms are not 
so abundant as in the Lower Chalk. The chalk at these localities 
is soft, and there should be no difficulty in obtaining specimens 
had they occurred. The list of the species identified by Mr. 
F. Chapman is as follows : — 
