90 



— at 306 feet deptb. A^ it is an adherent form, tlie absence of 

 objects from the fine silt -of the upper portions of the section, 

 which are necessary for tbe preservation of this form, may 

 account for its absence in the higber horizons. The examples 

 found are attacbed to fragments of shell or small flakes of 

 sbale, but in none of tbese is the spiralline form apparent. Its 

 geological bistory dates from tbe Lower Lias of France ; it is 

 also found in tbe Lias of France and England, and tbe Lower- 

 Oolite and Cretaceous rocks of Europe, but bas not been found 

 in any of tbe Tertiaries. 



Lingulina carinata, d'Orb. — The genus LinguUna represents- 

 simply a compressed and straigbt N'odosaria. The genus is- 

 scarce in tbe seas of tbe present day, except in the tropical and 

 subtropical portions of the Atlantic. It is known to exist as- 

 far back as tbe Lias, but it appears to bave been always a form 

 possessing but a limited distribution. L. carinata is tbe only 

 species of tbe genus tbat occurs in tbe Hergott section, and but 

 two examples were found. They agree with the figures usually 

 given of tbis species, but one of tbe examples obtained bas a 

 peculiar inflation of tbe last segment, whicb is botb larger and 

 rounder than tbe earlier cbambers, and approacbes very closely 

 to tbe Nodosarian cbaracter. 



CristeUaria rotulata^ Lamk. — Two or three fragments appa- 

 rently belonging to tbis species bare been found at Hergott. 

 ISTo perfect examples bave been procured, but by comparing tbe- 

 mucb-weatbered fragments one witb another it seems mode- 

 rately certain tbat tbe above is tbe species to wbicb they belong. 

 Tbis is perbaps tbe most widely distributed of all the Eora- 

 minifera, botb as to geograpbical limits and batb3'metrical 

 range, as well as geological time. It is recorded as belonging 

 to almost all geological formations from tbe Tapper Trias of 

 Derbysbire downwards. 



CristeUaria gihha, d'Orb. — Tbis is a variation of C. rotulata 

 in tbe direction of C. crepiduJa. Tbat is, tbe oral extremity is 

 drawn out so as to give an oblong shape to tbe sbell, wbicb is 

 compressed. There are often found a complete series of forms 

 from the almost circular C. rotulata to tbe extremely drawn out 

 G. crepidula, witb every sbade of intermediate modification. 

 D'Orbigny's C. gihha stands for tbe intermediate stage wben 

 tbe crepidulate tendency bas been arrested. Its distribution 

 is confounded witb allied varieties. Mr. Brady notes its oc- 

 currence in Xorth Atlantic and South Pacific at less than 500 

 fatboms. Its geological range bas bitherto dated from the 

 Cretaceous downwards. Tbe examples in the bore material are 

 few, but cbaracteristic. 



Marginulina glahra, d'Orb. — Tbis genus unites tbe Cristel- 

 larian and Xodosarian features, witb a marginal aperture ; and 



