4 



THE GEOLOGIST. 



Coq.j and the Natica Sautieri, Coq. The typical localities are, the 

 Auberson Valley, near St. Croix, St. Cergnes, and Les Rousses. 



(c). The Metabief Limonite {Limonite de Jletahief), forty feet thick, 

 is generally a reddish limestone, containing oolitic iron-ore ; the 

 strata are thin, and easily decomposed by atmospheric action. In 

 some places, as in the valley of Nozeroy, blue marls exist at the base 

 of this division. The fossils are very numerous, and beautifully pre- 

 served ; those characteristic are — Chelonia Valenginiensis, Pic. ; Croco- 

 dile ; Pledosaurus Neocomiensis, Camp. ; Pycnodus cyUndrims, Pic. j 

 Asteracanthus granulosus, Eger.j Ammonites Gevrilianus, D'Orb. ; A. 

 Marcousanus, D'Orb. ; Nerinea Marci)usana, D'Orb. ; Pholadomya 

 Scheuzeri, Agass. j Py gurus rostratus, Agass. ; Hemic idaris patella, 

 Agass.; Acrocidaris depressa, Gras.; C atopy gus Eenaudi, Agass.; &c. 

 Tj^Dical localities : Metabief, Boucheraus, and St. Croix. 



The Middle Xeocomian, or the Chateau group, as it is called in 

 reference to the castle of the town of Neuchatel, the foundation of 

 which rests entirely on this group, is composed of three divisions ; 

 {a) the Hauterive clay, (h) the Ecluse rocks, and (c) the yellow, or 

 Neuchatel stone. 



(a). The Hauterive clay (Mames d'' Hauterive), thirty feet thick, 

 consists of blue and sometimes plastic clay, with more or less of a 

 yellow tint and very numerous fossils; the most common are, Toxaster 

 coniplanatus, Agass.; Biadema rotulare, Aga,ss. ; Terehratula prcelonga. 

 Sow.; Ter. Marcousana, D'Orb.; Rhynclionella depressa, D'Orb.; Ostrea 

 Couloni, Defr.; Cor^his cordiformis, D'Orb. ; Trigonia caudata, Agass.; 

 Venus Diqyiniana, D'Orb. ; PanopeaNeocomiensis, Agass . ; Cardium Voltzii, 

 Leym. ; Pleurotomaria J^eocomiemis, Agass., &c. It is easy to distin- 

 guish three zones in these clays, characterised by different associations 

 of fossils ; the lower zone, or Censeau beds, the middle, and the upper 

 zone. Typical localities : Hauterive, neai' Neuchatel, St. Croix, Cen- 

 seau, Nozeroy, &c. 



(6). The Ecluse rocks {Roches de VEcluse), forty feet thick, are com- 

 posed of yellowish, often green, spotted limestone, alternating near the 

 base with yellow marls. Characteristic fossils : Rhynclionella depressa, 

 Sow. ; Ostrea Bousingaultii, D'Orb.; Lima Royeriana, D'Orb. ; Pecten 

 Cottaldinu^, D'Orb., etc. Typical localities: the Ecluse behind Neu- 

 chatel Castle, and Censeau. 



