TIEYIEW. 



399 



up as usual of those little oysters from wliicli it takes its name, and is 

 sometimes twenty metres tliick. The Great Oolite is a very massive lime- 

 storie, the upi)er ])art of which has been, rif^litly or wron^^ly, considered 

 by some Continental £reolo<i;is(s as re})resentin<^ our Forest Marble. The 

 ])((1le Nacree (Nacreous Marble) is a small limestone series cnclosinj^ at 

 its base subordinate beds of clny. Tlic ])rincipal fossils of the Dalle 

 NacrSe are Ammonites macroc('j)//((//fs. Sclil. ; Am. suh-hdch-cr 'ur, D'Orb. ; 

 Plioladomya huccarilium, Ag. ; J^. V^ezelayi, Laj. ; Lyonsia pererfrina, 

 Phill., sp. ; Lavicnion mactroides, D'Orb. ; Gervillia aeuta, Sow. ; Ostrea 

 acnminula, Sow. ; O. costata. Sow. ; Hhynchoyiella cuncinna, Sow., sp. ; 

 H. TAeteni, D'Orl). ; Tcrebratida difjuna, Sow, In the Efage O.rfordien, 

 M. Contejean includes the Callovian and Oxfordian J^lnfres of D'(3rbigny, 

 and consequently in the Montbelinrd re^]jion he admits in that ^roup the 

 _/*er Sous -Oxford} en (Callovian), the Marnes O.rfordiennes ((Jxfordian), 

 and the Calcaires a Spharites (Ar^ovian). 



His Efac/e CoralUen is the Etage Corallien of D'Orbii^ny, less the Cal- 

 caires a Astartes. It bef^ins with the Argilles a Chailles ; to these suc- 

 ceed the Calcaires Coralliens proper, which, in the Haut-Jura exceed a 

 jumdred metres in thickness, ^and it is terminated by the Coralline Oolite 

 (Oolithe Corallicrnu^). The l^]ta_£>;e Kimmeridien is made also by M. Conte- 

 jean to include the Etages Kimmeridien and Portlandien of D'Orbi<^ny, and 

 it is this group which most especially occupies the general surface of the 

 Montbcliard arrondissement. The four divisions of this elage are the 

 Aslartien, Pterocericn, Virgidien, and Neriueen. 



Between the Portland dolomite and the lowest Neocomian beds there are 

 intercalated, in man}^ localities, beds which have exercised the wits of many 

 geologists, and have given rise to much controversy. These are the Argiles 

 des f 'illiers, a small freshwater formation, considered by some to belong to 

 the Jurassic period, corresponding to the Purbeck beds, and by others as 

 representing the Weald Clay ; whilst others attach them to the Cretaceous 

 Formation. The author expresses no opinion on this point, but points out 

 the occurrence of these clays at Villiers-le-Lac, near Morteau, and as oc- 

 curring also generally at the base of the Neocomian deposits in the canton 

 of lJussey, in very variable thickness, but on the average about 10 metres. 

 Tlieir colour is dark grey, almost black. The fossils are rare and badl}^ 

 ])reserved. M. Lory has noted Fhysa Bristovii, Forbes [P. Wcahli(()ia. 

 Coq ), Planorbis Lorii, Coq., Corhula alata, Sow., and undetermined spe- 

 cies of Paludina, Lymneus, and Cyclas. 



The Cretaceous rocks are represented by Neocomian limestones, sur- 

 mounted by bands of limonite-iron — the Valencjinian group; or as M. 

 Contejean prefers to call them, the Calcaire a Limojiitc, and the Marnes de 

 d' Hauterive and the Calcaires de Ncuchdtel. The Calcaire a Chama (Ne- 

 gonien, D'Orb.) does not exist in the arrondissement, nor are any of the 

 Upper Cretaceous beds to be met with. 



The Terrain SideroUthique is another small formation which has occa- 

 sioned discussion as to its origin, and the place it ought to occu])y in the 

 geological series. It consists of clays, sands, and grains of iron, confusedly 

 ]ieai)ed in the fissures and 0])en depressions of all the Jurassic beds. The 

 iron is worked in numerous places, and some of the mines are very im- 

 portant. 



The Molasse extends from the north-east of ^NTonlbeliard over the terri- 

 tories of Sochaux, l^^xiucourl, ]^ilu])es, Brognard, I)and)enois, and Allan- 

 joie. Isolated by erosions, it foiMus low and rounch^l iiills. At Montaineau 

 the Molasse begins with strong beds of conglomerates of rounded pebbles 

 belonging to the Jurassic beds, and often preserving their fossils. These 



