PEOTOZOA- — FOEAMINIFEEA. 



23 



' Challenger ' are shown in a special Case in the middle of Gallery X. 

 this Gallery. 



It is natural, therefore, that Foraminifera should not 

 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 Table-case 

 may be seen limestones composed of the Astrorhizid genus 16. 

 Saccammina from Britain, of the Lituolid Endothyra from Wall-case 

 Indiana, and the Nummulitid Fusidina from Eussia ; also 9b. 

 isolated shells of Archaediscits, a primitive ISTummulitid, of Tabl^case 

 the Lacfenids JJentalina and Nodosaria, and of Texhtlaria. 

 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 the irregular adherent Lituolid, Wehbina. The Cretaceous 

 system furnishes greensands, in which, as above explained, 

 the actual shells are rarely preserved ; but some fragments 

 with the large Rotaliid Patellina are shown in both the 

 British and foreign series. Its characteristic rock, however, 

 is the white Chalk, which in some parts approaches a 

 Glohigerina ooze, and contains numerous shells of G-lohigerina, 

 Cristellaria, Nodosaria, Textularia, Litiiola, and other genera 

 (Fig. 4 h). These may be preserved in flint, and many such 

 figured in the Rev. H. Eley's Geology in the Garden " 

 (1859) are in the British Case. From the Maestrichtian 

 Chalk are shown the flat circular Orhitoides and the spurred Wall-case 

 Calcarina. As examples of Eocene limestones, mainly ®- 

 formed by Foraminifera, may be noted the Paris building- 

 stone with Miliola, an Alveolina limestone from Persia and 

 from Selsea, a French rock with Orhitolites, and another with 

 Orhitoides from both Biarritz and India. During the same 

 period were formed the various I^'ummulitic 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 Table-case 

 smaller forms obtained by washing the London Clay, and l^- 

 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 



