ZONE OF AMMONITES RARICOSTATUS. 



75 



species, kindly sent me in exchange, from the Royal Museum of Stuttgard, by Professor 

 Fraas which could not be distinguished from ours if they were not previously marked for 

 identification. 



Fossils of tlie Zone o/" Ammonites oxynotus. 



Ammonites oxynotus, Quenstt 



— bifer. Querist. 



— lacunatus, Buck. 

 Nautilus striatus, Sow. 

 Belemnites acutus, Mill. 

 Pleurotomaria Anglica, Som. 



Plicatula ventricosa, Munst. 

 Modiola minima, Sow. 

 Area oxynoti, Wr., n. sp. . 

 Leda Romani, Oppel. 

 Acrosalenia minuta. Buck. 

 Murieated spines of Cidaris. 



6. The Zome of Ammonites raricostatus. 



Synonyms. — " Hippopodium-bed (in part)," Murchison's ' Geology of Cheltenham,' 

 2nd ed., by Buckman and Strickland, p. 44. " Raricostatenschicht," Fraas, ' Wiirttemb. 

 naturvv. Jahreshefte,' 1847, pi. 3. " Raricostatenbank," Quenstedt, 1856, ' der Jura,' 

 p. 292. "Die Schichten des Ammonites raricostatus" Oppel, 1856, 'die Juraforma- 

 tion,' p. 56. " Raricostatus-bed," Wright, ' Quart. Jour. Geol. Soc.,' vol. xiv, p. 25. 

 " Zone of Ammonites raricostatus" Wright, ' Quart. Jour. Geol. Soc.,' vol. xvi, p. 407. 



The beds forming this zone are exposed in several brick-fields in the vicinity of 

 Cheltenham. They consist of dark-coloured clays, more or less impregnated with the 

 peroxide of iron. In an excavation recently made near Marie Hill, for the purpose of 

 obtaining clay to make bricks for the town-sewers, the following section was obtained. 

 The beds are enumerated in descending order. 



No. ft. in. 



1. GryphcBa-bed ; a hard, ferruginous clay, whieh broke into fragments, and contained 



a great many specimens of Gry/3A«a oS^ig'Maf a. Sow 3 ft. to 4 



2. Coral-band ; a thin seam of lightish-coloured, unctuous clay, containing a great 



many small, sessile Corals, Thecocyathus rugosus, Wr., most of which appeared to 



have been attached to the curved valves of the G'ry/^A^tE I in. to 1^ 



3. Sippopodium-bed ; a stiff, dark-coloured clay, in some parts ferruginous ; con- 



taining Cardmia Listen, Sow., and Hippopodium ponderosum, Sow., in consider- 

 able numbers from 8 ft. to 10 



4. Ammonite-bed ; a dark, ferruginous clay, containing selenite, with the peroxide and~| 



sulphuret of iron, and great numbers of a highly pyritic brood of Ammonites, r 

 likewise Am. raricostatus, Am, armatus, and the other species of the list J 



In the parish of Cleeve, near Cheltenham, the same beds were formerly worked for 



