the Nomenclature of the Foraminifera. 227 



IV. The deposit that yielded the Diatomaceae (" Poly- 

 gastrica," Ehr.) and Foraminifera figured in plate xxi. was 

 a white finely laminated calcareous and diatomaceous deposit 

 containing numerous well-preserved impressions of fishes. 

 This so-called "marl," also termed " Infusoria - conglo- 

 merate," "Tripoli-marl," and " Tripoli " by Ehrenberg, was 

 found by M. Rozet, as two layers, with some calcareous 

 and sandy beds, containing Ostrece and Gryphcece^ between 

 them ; and all of them occur among white chalk-like lime- 

 stones and yellowish marls, with Ostrece. &c., in the plain 

 east of Oran and extending to the Atlas. M. Rozet re- 

 garded these deposits as of Tertiary age ; but Dr. Ehrenberg 

 referred them to the Cretaceous series, on account of his 

 determination of the same kinds of " Polygastrica " and 

 " Polythalamia" in them as in other beds regarded by him as 

 Cretaceous. He considers this Oran Tripoli to be equivalent 

 to a similar white diatomaceous and calcareous earthy bed, 

 with fish-remains, that is found in Sicily (see further on). 

 This latter deposit is characterized by Clupea tenuissima, 

 and, like that of Oran, has been classified among the Tertiary 

 formations ; nor does there appear any valid reason, based 

 on its Microzoa, to group it otherwise. 



Shaly TrijJoU-hedj from Oran^ Africa. Abounding with 

 Diatoms and Polycystines, (Abhandl. Berl. Akad. Wiss. 

 1838, table no. 4, and fig. x. Monatsber. 1840 ; 1844, pp. 62, 

 73, &c. Ann. Nat. Hist. vol. vii. p. 312.) 



Plate xxi. figs. 1-81 comprise Diatomacese, Polycystina, 

 Spongoliths, &c. 



Fig. 82, Grammostomum crihrum (1844, pp. 67, 93),= Bo- 

 Uvina diJatata. Fig. 83, Proroporus lingua (1844, pp. 67, 95), 

 = -S(9/.^jz<«cto/a, with slight indications of ribbing, and therein 

 approaching to costata. Fig. 84, Gr. plica (1844, pp. 67, 93), 

 and fig. 85, Gr. aciculatum (1844), are Bol. punctata. Fig. 86, 

 Gr. divergens (1844, pp. 67, 93), =5. dilatata. Fig. 87, Tex- 

 tilaria globulosa (1844), is a small T. gihhosa. Fig. 88, Stro- 

 phoconus africanus (1844, pp. 68, 96), is a young Virgulina 

 Hemprichii. Fig. 89, Planulina perforata (1844), fig. 90 a, ^, 

 Rotalia globulosa (1838, 1844), and fig. 91, PI. oceUata (1844, 

 p. 67), are young individuals of Glohigerina buUoides. Fig. 92, 

 Prorospira princep)s ("1844, pp. 67,95, =Planulina turgida, 

 1844, young"), = Planorhulina anmionoides. Fig. 93, Pr. 

 comes (1844, pp. 67, 95), is a variety near PI. ammonoides. 

 Fig. 94, Planulina squaviula (1844, pp. 67, 94), is a small 

 XimhaiQ Planorhulina. Fig. 95, PI. spatiosa, is a large, broad- 



16* 



