PROTOZOA — FORAMINIFEEA. 
23 
merely be common fossils, but that they should have helped 
to build up large masses of rock. From Cambrian to 
Devonian times they are rare, and no specimens of those 
periods are exhibited. Among the Carboniferous specimens 
may be seen limestones composed of the Astrorhizid genus 
Saccammina from Britain, of the Lituolid Endothyra from 
Indiana, and the Xummulitid Fusulina from Eussia ; also 
isolated shells of Archaediscus, a primitive Nummulitid, of 
the Lagenids iJentalina and Nodosaria, and of Text%daria. 
The last two genera also occur among, the foreign Permian 
specimens, and Trochammina, a Lituolid, among those from 
Britain. 
The Jurassic marls and shales contain immense numbers, 
mostly of the small perforate and arenaceous forms 
not easily placed on exhibition. Among the British 
specimens from the Oxford clay is an oyster-shell covered 
with tlie irregular adherent Lituolid, Webbina. The Cretaceous 
system furnishes greensands, in which, as above explained, 
the actual shells are rarely preserved ; but some fragments 
with tlie large Kotaliid Patellina are shown in both the 
British and foreign series. Its characteristic rock, however, 
is the white Chalk, which in some parts approaches a 
Globiyerina ooze, and contains numerous shells of Glohiyerina, 
Cnstdlaria, Nodosaria, Textularia, Lituola, and other genera 
(Fig. 4 h). These may be preserved in flint, and many such 
figured in the Eev. H. Eley’s “ Geology in the Garden ” 
(1859) are in the British Case. From the Maestrichtian 
Chalk are shown the flat circular Orhitaides and the spurred 
Calcarina. 
As examples of Eocene limestones, mainly formed 
by Foraminifera, may be noted the Paris building-stone 
witli Miliola, an Alveolina limestone from Persia and from 
Selsea, a French rock with Orbitolites, and another with 
Orbitoides from both Biarritz and India. During the same 
period were formed the various Nummulitic limestones, of 
which numerous examples are shown from countries round 
the Mediterranean, also from S.E. Africa and India, while in 
the British series are specimens of the slighter development 
at Alum Bay and Bracklesham. Here also are many 
smaller forms obtained by washing the London Clay, and 
others of Pliocene Age from the Coralline Crag of Suffolk. 
The Nummulites have attracted the attention of learned 
writers from Strabo downwards, but have recently acquired 
fresh interest owing to a curious jn-oblem connected with the 
Gallery X. 
Table-case 
16. 
Wall-case 
9b. 
Table-case 
16. 
Wall-case 
I 9. 
Table-case 
16. 
