JURASSIC OF THE PAEIS BASIN. 



517 



Various changes have since been made in this classification, partly 

 by way of expansion, but partly by way of alteration ; and an 

 almost interminable series of Notes by M. Tombeck have led to the 

 development of a classification which is exceedingly complicated, and 

 which in several important points it seems impossible to accept. 

 As published by MM. De Loriol, Royer, and Tombeck (50), and 

 modified by the last named (55), it is as follows : — 



Portland ian. 



1. Zone of Cyrena ragosa. 



a. Upper grey-green limestones. 



b. Vacuolar oolite.. 



c. Lower grey-green limestones. 



2. Zone of Cyprina Brongniarti. 



a. Tubulous limestones. 



b. Spotted limestones. 



c. Carious limestones. 



3. Zone of Ammonites gig as. 



a. Bure oolite. 



6. Limestone with Amm. irius. 



c. Marls with Hemicidaris purbeeJcensis. 



d. Lithographic limestone with Amm. rotundas. 



KlMMERIDGlAN. 



1. Zone of Amm. caletanus, = Virgulian. 



a. Alternations with Amm. erinus. 



b. Marls with Amm. eumelus. 



2. Zone of Amm. orthocera, = Pterocerian. 



a. Perforated limestones. 



b. Marly limeston es with Dysaster granulosus. 



c. Limestone with Isocardia striata. 



d. Marls with Rhalidocidaris Orbignyana. 



e. Marls with Ceromya excentrica. 



f. Perforated limestone with Pteroceras. 



CORALLIAN OR SeQUANIAN. 



1. Second zone of Terebratula humeralis. 



Astartian limestone. 



2. Second zone of Cardium corallinum. 



La-Mothe oolite. 



3. First zone of Terebratula humeralis. 



a. Lithographic limestones. 



b. Saucourt oolite. 



c. Limestones with Nautilus giganteus. 



d. Upper rubbly limestone with Cidaris florigemma. 



e. Limestone with Amm. achilles. 



f. Limestone with Amm. bimammatus. 



4. First zone of Cardium corallinum, and zone of Hemieidaris 



crenularis. 



a. Upper marls without fossils. 



b. Diceras-oolites, and lower rubbly limestones with Cidaris 

 florigemma. 



c. Lower marls without fossils. 



OXFORDIAN. 



Zone of Amm. transversarius. 



a. Beds with Amm. Henrici and Amm. oculatus. 



b. Beds with Amm. Babeanus. 



c. Beds with Amm. Martelli. 



