Sullivan & O'Reilly— On Dolomite Bed of North of Spain. 229 
the cretaceous rocks as provisional, especially as regards the lower 
members of the series. 
"We may now return to M. Coquand's investigations. According 
to that geologist there occurs in the neighbourhood of Marseilles a 
mass of dolomite of about one hundred and fifty metres thick, which 
rests upon the upper Oxford series. Above the dolomite come a 
series of limestone beds about 100 metres thick, in which are found 
some badly-preserved nerineas and corals. These coralline limestone 
beds form the upper part of the Jura, and are very sharply separated 
from the overlying valenginian. M. Coquand looks upon these beds 
as the representatives of the kimmeridge. As the badly-preserved 
fossils afford very little paleontological evidence this opinion must be 
chiefly based on stratigraphical considerations. Herr Zittel thinks 
that they represent exactly the beds of Eogoznik, and correspond to 
the coralline limestone of Inwald, Pirgl, Mont Saleve, and Wim- 
mis. 
In the neighbourhood of Ganges, Saint Hippolyte, and Saumene, 
in the Cevennes, M. Coquand has also found a great bed of dolomite 
above the ''Zone of Ammonites polyplocus, and A. tenuilobatus," con- 
taining, sparingly, as at Marseilles, badly-preserved fossil remains. 
Here, too, the dolomite is succeeded by well-bedded solid white lime- 
stone, 180 metres thick. This limestone is more fossiliferous than 
the corresponding one near Marseilles, being here and there filled nest- 
wise with fossil remains. The Marseilles limestone also contains in 
some places, as at Cazillac, Eois de Mounier, and Eans, numerous 
easily-determinable fossils. The fauna of this limestone in both 
districts consists principally of Gasteropods, Elatobranchs, Brachiopods, 
and corals. The total habitus of this fauna is decidedly upper jura- 
sic. Herr Zittel is of opinion that this limestone offers the same facies 
as that of the Eogoznik beds of the Carpathians, as at Inwald, Mont 
Saleve, and Wimmis. It occupies exactly the same stratigraphical 
position as the diphya limestone in the Southern Alps, and the shelly 
breccia of Eogoznik. He thinks that the concurrent testimony of 
MM. Coquand and Hebert shows it to be paleontologically identical 
with the coral rag of Mont Saleve and Inwald. 
M. Coquand's description of these Southern French rocks agrees 
so well with the character of the Dolomite and overlying limestone of 
Santander, especially as seen in the valleys of Comillas, Pelurgo, and 
Udias, that there can be little doubt that they belong to the same 
horizon, and that the Tithonic Stage extends beyond the Pyrenees. 
If, as there is every reason to believe, the dolomite was formed in a 
deep inland sea, we have in this enormous fringe of rocks, included 
under the term Tithonic Stage, and extending almost unbroken from 
nearly the Black Sea to the Atlantic Ocean, evidence of the existence 
of a great Mediterranean Sea at the close of the Jurassic period of even 
far larger dimensions than the present one. 
Nor are the rocks included in the Tithonic Stage confined to the 
Biscayan coast ; investigations carried out in other districts of Spain 
