284 THE CRETACEOUS ROCKS OF BRITAIN. 
It only remains to record the lower beds of this zone at Speeton 
(Seep. 230 ). In that immediately overlying the Bed Chalk (23) 
fine inorganic sediment again appears to be mixed with the cal¬ 
careous mud, and is accompanied by fine sand. “ Spheres ” are 
still abundant, Foraminifera occur, and are chiefly Globigerince 
with a few species of Textularia and Rotalinci. Shell-fragments 
are rare. Glauconite seems absent. The bed passes up into normal 
Chalk-Marl of the Yorkshire type which, though stained a deep 
red, differs in no other way from the ordinary rock at this 
horizon. Above this the marl becomes shelly, (25) and for 8 or 
10 feet very coarse shell-fragments ‘abound, especially in the 
material which surrounds the nodule-like masses in the bed. This 
condition gradually passes away upward, and the desposit again 
assumes its normal character, and consists largely of fine amor¬ 
phous matter with a few “ spheres," G-lobigerincv or other Fora¬ 
minifera with shell-fragments of irregular size. 
Examination of the Washings. 
Under this heading we give a description of the chief features 
of the coarsei* materials obtained by washing the various speci¬ 
mens, including the Foraminifera obtained from the coarser residues 
after the action of the acid solution. 
Little information could be obtained by this means from the 
hard indurated chalk-marls of the West of England or the hard 
chalk of this zone in Lincolnshire and Yorkshire, but from the 
softer marls of Kent, those of Charlton and Arlsey, in Bedford¬ 
shire, and that from Barrington, in Cambridgeshire, better results 
were obtained. The coarser organic ingredients were practically 
the same in all localities, though they differed slightly in the relative 
abundance of the various organisms. The following remarks 
refer especially to those softer beds, unless other localities are men 
tioned. 
Shell-fragments. — These were chiefly prisms of Inoeeramus- 
shell, or larger fragments showing the prismatic structure; here 
and there a bit of Pecten, Rhynchonella, Ostrea, or Plicatula could 
be detected. Small Echinoderm spines occurred in them all, but 
were most numerous in the marl from Barrington, Cambridgeshire, 
ten feet above the Cambridge Greensand. They may be referred 
to Hemiaster or Pseudodiadema. Fragments of Bryozoa are also 
fairly numerous. 
Sponge Spicules.— The spicular remains of sponges, are never 
very numerous except in the beds referred to on p. 279. Hexactinellid 
mesh, with both Tetractinellid and Monactinellid spicules occur 
in the marls of South Dorset, and the Isle of Wight, (Compton Bay). 
Between the West of England and north Norfolk spicules 
are comparatively rare, though in the lower part of the Marl at 
Dover both Tetractinellid and Monactinellid spicules occur. Bods 
