tjuith an Account of some new Foraminifera. 273 



stone, often nodular, divided by clay; and contains numerous 

 fossils, viz. the characteristic GrypJuBa incurva, Lima gigantea, 

 Gervillia, Avicula, Pecten, Nautilus, Ammonites, spines and plates 

 of Echinoderms, and a few other shells. The lower bands pre- 

 sent the usual alternations of blue limestone and shales, which 

 are often loaded with broken joints of Pentacrinites, amongst 

 which a few heads of the rarer Pentacrinites tuberculatum (jNIiller) 

 have been met with. This cliff, however, is particularly interesting, 

 from the occurrence of a new and fine species of the Brachiopod*, 

 Orbicula Townshendi (named after the discoverer), and one of 

 the Foraminifera which I lately found, and which ]Mr. Rupert 

 Jones beheves will prove to be a true Nummulitef. They occur 

 in a particular part of the cliff near the centre, and seem to be 

 confined to one or two bands of limestone, the weathered sur- 

 faces of which occasionally are covered with them, though, 

 from the highly crystalline state in which these mimute fossils 

 are preserved, it is extremely difficult to make out their in- 

 ternal structure. This is the first occurrence of this genus 

 in England in any stratum older than the Eocene (Tertiary) 

 group, and was hitherto supposed to be confined to the Tertiary 

 series. Ehrenberg proved long ago that many of these minute 

 organisms among the Foraminifera (which form so important a 

 part in the composition of many rocks), from the Chalk upwards, 

 had continued to exist even to the present day, while the con- 

 temporary forms of a higher order had become extinct, and we 

 may therefore feel less surprise at the presence of a true Num- 

 mulite even so low down in the secondary series as the Lias, 

 although we have no trace of the same genus again until a com- 

 paratively recent epoch, a wide interval of time having elapsed 

 between its supposed first creation and its reappearance in pro- 

 fusion in the Tertiary series. So abundant are some of these 

 fossils in some places abroad, that vast masses of tertiary limestone 

 are entirely composed of them, and in the Lias at Fretheme they 

 are generally grouped together in masses. 



M. Bouvigny has lately described and figured a NummuliteX 

 from certain Jurassic strata on the continent, namely the lower 

 marls belonging to the calcaire a Astartes, which occurs between 

 the Kimmeridge Clay and the Coral Rag. I had previously 



* Mr. C. Moore has lately found several new species o{ Brachiopoda in the 

 upper Lias in Somersetshire, and one very curious shell which he thinks 

 may belong to a new genus, having two bosses at the side. Deslongchamps 

 has also detected several new forms belonging to this order in the upper 

 Lias of Normandy, amongst which is a Leptana of large size ; all those pre- 

 viously discovered by Mr. Moore near Ilminster being extremely minute. 

 See Mr. Davidson's "Monograph : Palaeontographical Society. 



t See Mr. Jones's Note, infra. 



X NummuUna Humbertina : see Geol. statistique, min^r. et paleont. de la 

 Meuse ; Atlas, p. 4?. pi. 31. f. 32-35. 



Ann. Sf Mag. N. Hist. Ser.2. Fo/. xii. 19 



