456 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 18, 



themselves, are all referable to the same specific type, which is suffi- 

 ciently well represented by the JV. lucifuga, Blainv., above referred to. 



The specimens from Chellaston comprise about a dozen individuals 

 (all very small), both of the rectilinear and the scale-like varieties. 

 The latter (N. lucifuga, PI. XX. figs. 52-56) are perfect, and from 

 the extreme thinness of the shell on the flat or attached side allow- 

 ing the pyritous casts to be seen, well exhibit the form and arrange- 

 ment of the chambers. Of the straight specimens (N. Tibia) we have 

 only fragments, the spiral portion being absent (figs. 48-51) ; they 

 appear to have been attached by flattened portions of the dilated 

 proximal end of the chamber, the long distal end being tubular. 



Comparison with other Fauna). — Taking the above-described group 

 of Foraminifera, from the Alabaster-pits of Chellaston, as a fair 

 sample of the marine microzoic fauna of the latest Triassic period, we 

 have to compare it with the Khizopodal faunae of the Liassic and 

 later periods, and with that of the present seas. The Upper Lias of 

 Ilminster and the Lias of Gottingen are known to be rich in Nodo- 

 sarince ; at Stockton in Warwickshire the Lias clay, several pounds 

 of which we have worked out with great care, yields abundance of 

 the JSfodosarince of the same species as, but of different varieties to, 

 those of Chellaston, associated with Quinquelocid'ma, Trochammina, 

 Botcdia ammonoides, and a variety related to B. elegans. 



In some of the clays of the Oolites we find not dissimilar faunae. 

 This is the case with two clays of the Middle Oolite (from near 

 Peterborough), in which, besides the Nodosarinw, Nubecularia, Tro- 

 chammina, Lituola, and Botcdia elegans, we have fine specimens of 

 Verneuilina equal in size to those of the Chalk. In the Oxford clay 

 a similar group of Nodosarince occurs together with Lituola, Nube- 

 cularia, Trochammina, Orthocerina, and Rotalia elegans. The Kim- 

 meridge clay yields also the Nodosarince in abundance, Nubecidaria), 

 Trochammina), Polymorphince, and Rotalia elegans, with Bulirnina 

 and numerous small forms of Textidaria. The Gault and the Chalk 

 abound with the Nodosarince and all the other forms above mentioned, 

 with the addition of Globigerina, Valvulina, and some others. 



Among the Tertiary deposits, a Pliocene clay from S. Quirico, Tus- 

 cany, presents a fauna most nearly allied to that of the Chellaston 

 clay in hand ; but it differs characteristically by the great abun- 

 dance of Olobigerince and Nonionince. The recent deposits most like 

 that of Chellaston are grey muds from the western part of the Medi- 

 terranean at about 750 fathoms, having abundance of minute Botalice 

 elegantes, small thin-shelled Bulimince, and delicate Nodosarince of 

 various conditions of form ; but these species are almost masked 

 by the extreme abundance of well-developed Orbulince and Globi- 

 gerince, and other Botalice besides B. elegans. A sounding off Lisbon 

 at about 700 fathoms, and one off Cape Finisterre, yielded some- 

 what similar results, the former presenting us with a form very 

 rare in the recent state, namely, a Frondicidaria. 



The annexed Table gives a synopsis of the different Faunae, and 

 serves as an explanation to Plates XIX. and XX., in which the 

 specimens are highly magnified. 



