224 



the Haute-Saone, Doubs and Jura. As this region was formerly 

 inhabited by a powerful Celtic race, the Sequani, their name 

 has been given to the group. M, Thurmanjst * described these 

 beds as they are seen at Mont-Terrible, — ^Ist, as Calcaires a 

 Astartes, Calcaires compactes, a cassure concho'ide, avec Astarte 

 minima et tres-peu de fossiles, 20 metres in thickness; 2nd, 

 Calcaires a Nerinees, Calcaires blancs, compactes-conchoi'des, ou 

 crayeux, avec Nerinees, 20 metres ; 3rd, Oolithe Gorallienne, 

 Calcaire oolithique, cannabines ou pisaire inegal, souvent sub- 

 cretace; relief superficiel de la decomposition des oohthes 

 presentant frequemment une concentricite remarquable, avec 

 Nerinoea Bruntrutana, JDiceras arietina, &c., 5^ metres. This 

 author erroneously considered them to be synchronous with the 

 English coral rag. 



M. Thikria t in his description of the Jura of the Haute- 

 Saone followed a like division of the Sequanien, as may be seen 

 in his section given at p. 21 7. M. Jules MAKCOTit has described 

 these strata in his groupe "Sequanien, Kimmeridien et Port- 

 landien" and establishes the synchronism of the Sequanien or 

 Groupe de Besan9on with the Calcaire a Astartes of the Haute- 

 Marne, the Meuse, the Cote-d'Or, and Haute-Saone, in his 

 Roches du Jura. § 



M. Etallon II divides the Terrain Jurassique Superieur into 

 two stages, — 1st, Calcaire Corallien. 2nd, Diceratien. The first 

 are the rocks that belong to the coral rag, and have been already 

 described : the second represent that portion of the Sequanien 

 which is characterized by Nerinees and Diceras. ^'Les Diceras 

 se trouvent en immense quantite ; c'est de beaueoup le fossile le 

 plus abondant, et parmi eux domine le Diceras Miinsteri, Goldf. 

 Diceras speciosa, Goldf., est aussi tres-commun, mais sa grande 



* Essai STir les Soulevemens Jurassiques du Porrentruy : 1832. 



t Statistique geolog. de la Haute-Sa6ne : 1833. 



X Recherclies sur les Jura salinois, p. 116 : 1846. 



§ Les Eoches du Jura, p. 174 : 1860. 



II Esquisse geol. du Haut-Jura, p. 47 : 1857. Statistique geolog. du Depart, 

 de la Meuse : 1852. 



