Geological Society of London. 285 



Five distinct areas were considered in this paper, a. The southern 

 range ; 6. The Charentes ; c. Normandy ; d. The Pays de Bray ; 

 e. The Boulonnais. 



a. The Southern Range. — This is continuous from the Ardennes 

 through the Meuse, Yonne, etc., to the Cher. In the Ardennes the 

 " Ferruginous Oolite " corresponds to our Osmington Oolite, and to 

 the Lower Limestones and Passage-beds of Yorkshire, the under- 

 lying " Middle Oxfordian " being equivalent to our Lower Cal- 

 careous Grit. Above comes immediately the Coral Bag with 

 Cidaris florigemma ; and the stratigraphical and palasontological 

 break is constantly between the Coral Bag and Ferruginous Oolite 

 when that occurs. The Corallian is a well-marked formation, 

 though its character is variability. It is divisible generally into two 

 groups — Coral Bag and Supracoralline beds, the latter usually being 

 the " Diceras-heds " ; but in the Yonne there is a great development 

 of Diceras-heds below, associated with Cidaris florigemma and 

 massive corals, which is gradually introduced in going west. This 

 part of the series in the Haute Marne has been described as very 

 different ; but the author did not at all agree with M. Tombeck's 

 stratigraphical determination, and considers the " Oolite de la Nothe" 

 no more than the continuation of the Supracoralline D«ceras-beds, 

 which he considers to uniformly overlie and never to underlie the 

 Am. marantianus marls, which latter are Oxfordian, In fact nothing 

 abnormal occurs in this Department. The whole series has a 

 tendency to degenerate into barren lithographic limestones, in which 

 distinctions are lost. The Astartian and Virgulian beds were traced 

 through this range, the latter seldom showing any well-marked 

 Pterocerian division, and the former being mostly connected with the 

 overlying series. Above these are limestones hitherto called " Port- 

 landian," in which two zones are constant ; but above all are vacuolar 

 Oolites, which alone may be truly correlated with the Portland rocks 

 of England. The Avhole of the beds in this range are eminently 

 calcareous, a true clay being scarcely anywhere seen. 



b. The Charentes. — In these two Departments the lower portion is 

 very calcareous, and the distinction of one part from another very 

 slight ; but the highest portion, both near Cognac and on the He 

 d'Oleron, yields beds which may be paralleled with our true English 

 Portland rocks. 



c. Normandy. — The complete sequence has here been made out, 

 from the true Oxford Clay of Dives to the Virgulian of Havre, and 

 the similarity of the whole to the sequence in Dorsetshire is very 

 remarkable. " The Trouville Oolite " is the exact representative of 

 the " Osmington Oolites " with the Nothe Grits below ; but the place 

 of the Sandsfoot clay is taken by the true Coral Bag, whose right 

 position in the Weymouth section is hereby determined. The 

 Supracoralline beds are the sands of Glos, and the Astartian beds 

 are the Trigonia-heds of Havre, which are the exact representatives 

 of the " Kimmeridge passage-beds." 



d. The Fays de Bray. — Nothing below the Virgulian is here seen, 

 and the commencement of the so-called " Portland beds " was con- 



