ZOiNE OF AMMONITES JURENSIS. 



89 



CONCHIFEIIA. 



Astarte lurida, Soto. 

 Positlononiya Bronni, Foils. 

 Nucula Ilaiismaiiui, Moem. 



— ovum, Sow. 

 Gresslya gregaria, Roetn. 

 Lima bellula, .' Lijc. and Mor. 

 — gigantea, ? Sow. 



Tancredia lacviuscula. Lye. 

 Placunopsis sparsicostatus, Lye. 

 Inoccraraus dubius, Sow. 

 Monotis substriata, Goldf. 

 Area inoequivalvis, Goldf. 

 Cucullaea Miiuster, Ziet. 



BRACHIOrODA. 



Leptsena Moorei, Dav. 



— liasina, Bouch. 



— granulosa, Dav. 

 Tliecidium nisticum, Moore. 



— Boucbardii, Dav. 

 Lingula Beanii, Phil. 



Spirifer Ilminsterensis. Dav. 



— Miinsteri. Dav. 

 Rbynchonella pygmaei, Mor. 

 Terebratula globulins, Dav. 

 — LyceUi, Dav. 



Acrosalenia crinifera, Querist. 

 Pseudodiadema Moorei, Wright. 



ECHINODERMATA. 



Pentacrinus. 



The Zone of Ammonites Jurensis. 



Synonyms. — "Lias Zeta," Quenstedt, 'Der Jura Uebersichtstafel,' p. 293. "Zone des 

 Amm. torulosus und zone des Amm. Jurensis," Oppel, ' Juraformation,' p. 296. " Marnes 

 d'Aresche, etMarnes de Pinperdu/' Marcou, franc- comtois, les Roches, 'Du Jura,' p. ]19, 

 " 9" etage Toarcien (pars, sup.)," d'Orbigny, ' Cours. element, de Paleontologie/ p. 469 

 (sect, at Thouars h to /). " Sands of the Inferior Oolite," Smith, De la Beche, Cony- 

 beare, and other English authors. " Cephalopoda bed and Upper Lias Sands," Wright, 

 'Quart. Jour. Geol. Soc.,' vol. xii, p. 292, 1856. "Ammonite Sands," Hull, 'Mem. of 

 the Geol. Surv. Country around Cheltenham,' p. 25, 1857. " Cynocephala stage," Lycett, 

 'Cotteswold Hills,' p. 16, 1857. "Jurensis bed," Wright, 'Quart. Jour. Geol. Soc.,' 

 vol. xiv, p. 25, 1857. 



This youngest member of the great Lias formation has a limited geographical range ; 

 for like other unconsolidated arenaceous deposits, it has been extensively affected by 

 denudation. It is well developed in the counties of Gloucester, Somerset and Dorset, 

 and at Blue Wick, on the Yorkshire coast. It may be advantageously studied at the 

 latter locality, and in the fine section at Frocester Hill, and in other smaller exposures in 

 the Nailsworth and Brimscombe Valleys in Gloucestershire. The following section of 



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